  C++ Programming HOW-TO
  Al Dev (Alavoor Vasudevan)        alavoor@yahoo.com
  v37.0, 27 April 2001

  This document provides a comprehensive list of C++ URL pointers, links
  to C++ online textbooks, and programming tips on C++. This document
  also provides a C++ library which imitates Java-language, and which
  has various methods to avoid memory problems in C++. Using this
  library you can compile Java's source code under C++.  This document
  serves as a "Home of C++ language".  The information given here will
  help you to program properly in C++ language and applies to all the
  operating systems that is - Linux, MS DOS, BeOS, Apple Macintosh OS,
  Microsoft Windows 95/98/NT/2000, OS/2, IBM OSes (MVS, AS/400 etc..),
  VAX VMS, Novell Netware, all flavors of Unix like Solaris, HPUX, AIX,
  SCO, Sinix, BSD, etc.. and to all other operating systems which sup­
  port "C++" compiler (it means almost all the operating systems on this
  planet).
  ______________________________________________________________________

  Table of Contents



  1. Introduction

     1.1 C++ v/s Java
     1.2 Which one Ada95, "C", "C++" or Java ??
     1.3 Problems facing the current C++ compilers
     1.4 COOP - C++ Object Oriented Programming-language

  2. String Class Varieties

     2.1 Multiple Inheritance - Sample Custom String class

  3. Download String

  4. Usage of String class

     4.1 Operators
     4.2 Functions

  5. String.h file

  6. Renaming the String class

     6.1 Case 1: Simple rename
     6.2 Case 2: Resolve conflict

  7. File Class

  8. C++ Zap (Delete) function

  9. Pointers are problems

  10. Usage of my_malloc and my_free

     10.1 Garbage Collector for C++

  11. Debug files

  12. Java like API

  13. IDE tools for C++

  14. C++ Online Textbooks and Docs

  15. C++ Coding Standards

  16. C++ Online Docs

     16.1 C++ Tutorials
     16.2 Useful links
     16.3 C++ Quick-Reference
     16.4 C++ Usenet Newsgroups

  17. Memory Tools

  18. Related URLs

  19. C++ Scripting Languages

     19.1 PIKE (C/C++ Scripting Language)
     19.2 PHP (C++ Scripting Language)

  20. Templates

  21. STL References

     21.1 Overview of the STL
     21.2 Header Files
     21.3 The Container Classes Interface
     21.4 Vectors
        21.4.1 Constructing Vectors
        21.4.2 Checking Up on Your Vector
        21.4.3 Accessing Elements of a Vector
        21.4.4 Inserting and Erasing Vector Elements
        21.4.5 Vector Iterators
        21.4.6 Comparing Vectors
     21.5 Iterators and the STL
     21.6 Lists
     21.7 Sets
        21.7.1 Constructing Sets
        21.7.2 What are Function Objects?
        21.7.3 A Printing Utility
        21.7.4 How Many Elements?
        21.7.5 Checking the Equality of Sets.
        21.7.6 Adding and Deleting Elements
        21.7.7 Finding Elements
        21.7.8 Set Theoretic Operations
     21.8 Maps
     21.9 STL Algorithms

  22. Threads in C++

     22.1 Threads Tutorial
     22.2 Designing a Thread Class in C++
        22.2.1 Introduction
        22.2.2 Brief Introduction To Threads
        22.2.3 Basic Approach
        22.2.4 The Implementation
        22.2.5 Using The Thread Class
        22.2.6 Conclusion

  23. C++ Utilities

  24. Other Formats of this Document

  25. Copyright

  26. Appendix A String Program Files



  ______________________________________________________________________

  1.  Introduction

  The purpose of this document is to provide you with a comprehensive
  list of URL pointers and programming tips on C++.  Also, this document
  provides a C++ library having Java-like String class, string
  tokenizer, memory functions and many other functions, which can be
  used in general C++ applications.  Also various examples are given
  here which demonstrate the usage of this library.

  This document is not a textbook on C++, and there are already several
  excellent "on-line Text books" on internet.  If you are new to C++ and
  you never programmed in C++, then it is strongly suggested that you
  first read the online C++ Textbooks given in the chapter ``C++ Online
  Textbooks'' and then follow the subsequent chapters. It is suggested
  that you purchase a textbook on C++ for reference from online
  bookstores like amazon <http://www.amazon.com> or barnes
  <http://www.barnesnoble.com>.



  1.1.  C++ v/s Java

  C++ is one of the most powerful language and will be used for a long
  time in the future inspite of emergence of Java. C++ runs extremely
  fast and is in fact  10 to 20 times FASTER than  Java. Java runs very
  slow because it is a byte-code-interpreted language running on top of
  "virtual machine".  Java runs faster with JIT (Just-In-Time) compiler,
  but it is still slower than C++. And optimized C++ program is about 3
  to 4 times faster than Java (with JIT compiler).  Then, why do people
  use Java? Because it is pure object oriented and is easier to program
  in Java, as Java automates memory management, and programmers do not
  directly deal with memory allocations. This document attempts to
  automate the memory management in C++ to make it much more easy to
  use.  The library given here will make C++ look like Java and will
  enable "C++" to compete with Java language.

  Because of manual memory allocations, debugging the C++ programs
  consumes a major portion of time. This document will give you some
  better ideas and tips to reduce the debugging time.

  1.2.  Which one Ada95, "C", "C++" or Java ??

  Language choice is very difficult. There are too many parameters -
  people, people skills, cost, tools, politics (even national politics)
  and influence of businessmen/commercial companies.  The best language
  based on technical merits does not get selected simply due to
  political decisions!

  Java is much closer to Ada95 than C++. Java is derived from Ada95.
  Ada95 gets the maximum points as per David Wheeler's Ada comparison
  chart <http://www.adahome.com/History/Steelman/steeltab.htm>.  Ada got
  93%, Java 72%, C++ 68% and C got 53%. C++ and Java are closer in
  points(only 4% difference), hence Java is not a very big revolution as
  compared to C++. On other hand, Ada is a very big revolution and
  improvement over C++.  The scores are like 4 students taking exams and
  student with highest score is Ada (93%). Who knows? Perhaps in future
  Ada95 will replace Java!!  Development costs of Ada is half of C++ as
  per Stephen F. Zeigler <http://sw-eng.falls-
  church.va.us/AdaIC/docs/reports/cada/cada_art.html>.  Ada95 is
  available at -

  ·  Ada home  <http://www.gnuada.org>.

  ·  Google Ada index
     <http://directory.google.com/Top/Computers/Programming/Languages/Ada>

  Since C++ programmers are abundant, it is recommended you do
  programming in object-oriented "C++" for all your application
  programming or general purpose programming. You can take full
  advantage of object oriented facilities of C++. The C++ compiler is
  lot more complex than "C" compiler and C++ programs may run bit slower
  than "C" programs. But speed difference between "C" and "C++" is very
  minute - it could be few milli-seconds which may have little impact
  for real-time programming.  Since computer hardware is becoming
  cheaper and faster and memory "C" as time saved in clarity and re-
  usability of C++ code offsets the slow speed.  Compiler optimizer
  options like -O or -O3 can speed up C++/C which is not available in
  Java.

  Nowadays, "C" language is primarily used for "systems programming" to
  develop operating systems, device drivers etc..

  Note: Using the String, StringBuffer, StringTokenizer and StringReader
  classes given in this howto, you can code in C++ which "exactly" looks
  like Java.  This document tries to close the gap between C++ and Java,
  by imitating Java classes in C++
  Java is platform independent language more suitable for developing GUI
  running inside web-browsers (Java applets) but runs very slow. Prefer
  to use web-server-side programming "Fast-CGI" with C++ and HTML,
  DHTML, XML to get better performance. Hence, the golden rule is "Web-
  server side programming use C++ and web-client side (browser)
  programming use Java applets".  The reason is - the server-side OS
  (Linux) is under your control and never changes, but you will never
  know what the client side web-browser OS is. It can be Internet
  appliance device (embedded linux+netscape) or computers running
  Windows 95/98/NT/2000 or Linux, Apple Mac, OS/2, Netware, Solaris
  etc..

  The advantage of Java language is that you can create "Applets (GUI)"
  which can run on any client OS platform.  Java was created to replace
  the Microsoft Windows 95/NT GUI APIs like MS Visual Basic or MS Visual
  C++.  In other words - "Java is the cross-platform Windows-GUI API
  language of next century".  Many web-browsers like Netscape supports
  Java applets and web-browser like Hot Java is written in java itself.
  But the price you pay for cross-platform portability is the
  performance, applications written in Java run very slow.

  Hence, Java runs on "client" and C++ runs on servers.

  1.3.  Problems facing the current C++ compilers

  Since C++ is super-set of C, it got all the bad features of "C"
  language.  Manual allocation and deallocation of memory is tedious and
  error prone (see ``Garbage Collector for C++'').

  In "C" programming - memory leaks, memory overflows are very common
  due to usage of features like -

  ______________________________________________________________________
          Datatype  char * and char[]
          String functions like strcpy, strcat, strncpy, strncat, etc..
          Memory functions like malloc, realloc, strdup, etc..
  ______________________________________________________________________



  The usage of char * and strcpy causes horrible memory problems due to
  "overflow", "fence past errors", "memory corruption", "step-on-others-
  toe" (hurting other variable's memory locations) or  "memory leaks".
  The memory problems are extremely hard to debug and are very time
  consuming to fix and trouble-shoot. Memory problems bring down the
  productivity of programmers. This document helps in increasing the
  productivity of programmers via different methods addressed to solve
  the memory defects in "C++".  Memory related bugs are very tough to
  crack, and even experienced programmers take several days or weeks to
  debug memory related problems. Memory bugs may be hide inside the code
  for several months and can cause unexpected program crashes. The
  memory bugs due to usage of char * and pointers in C/C++ is costing $2
  billion every year in time lost due to debugging and downtime of
  programs. If you use char * and pointers in C++ then it is a very
  costly affair, especially if your program size is greater than 10,000
  lines of code.

  Hence, the following techniques are proposed to overcome the faults of
  "C" language. Give preference in the following order -

  1. Use references instead of pointers.

  2. Java style String class (given in this howto) or STDLib string
     class.


  3. Character pointers (char *) in C++ limit the usage of char * to
     cases where you cannot use the String class.

  4. Character pointers (char *) in C using extern linkage
     specification, if you do not want to use (char *) in C++.

  To use "C char *", you would put all your "C" programs in a separate
  file and link to "C++" programs using the linkage-specification
  statement extern "C"  -

  ______________________________________________________________________
  extern "C" {
  #include <stdlib.h>
  }

  extern "C" {
          comp();
          some_c_function();
  }
  ______________________________________________________________________



  The extern "C" is a linkage specification and is a flag that
  everything within the enclosing block (brace-surrounded) uses C
  linkage, not C++ linkage.

  The utilises the constructor and destructor features to automate
  memory management and provides access to functions like ltrim,
  substring, etc..

  See also related in the C++ compiler.  The string class is part of the
  standard GNU C++ library and provides many string manipulation
  functions.  Because the C++ library provides many string manipulation
  functions, there is less need to use the character pointer approach to
  write your own string functions.  Also, C++ programmers must be
  encouraged to use 'new', 'delete' operators instead of using 'malloc'
  or 'free'.

  The does everything that char * or char [] does. It can completely
  replace char datatype. Plus added benefit is that programmers do not
  have to worry about the memory problems and memory allocation at all.

  1.4.  COOP - C++ Object Oriented Programming-language

  A problem with C++ is that it is a superset of C, and, although
  programmers can use the good (object oriented) features of C++ and
  avoid the bad features of C, there is nothing to force them to do so.
  So, many C++ programs are written with no object oriented features and
  continue to use the bad features of C that the use of C++ should have
  overcome.

  Therefore, I propose that we create a new version of C++ that does not
  allow the use of the bad features of C.

  I propose that this new version of C++ be called COOP (say koop),
  which is an acronym for C++
   Object
   Oriented
   Programming-language" . COOP should be pronounced like chicken coop.
  (The logo of COOP language is a big fat Hen inside coop!)  I propose
  that the file extension for COOP files be .coo, which will not
  conflict with .c for C programs or .cpp for C++ programs.

  To begin with, write the COOP as a front end to C++. That is COOP pre-
  processes the code syntax and then uses the standard C++ compiler to
  compile the program.  COOP acts as a front end to C++ compiler. (To
  start with, COOP will be a very good project/thesis topic for
  university students)

  The following are some other proposed features of COOP:

  ·  COOP will borrow some best ideas from Microsoft C#, Microsoft put
     lot of efforts, and you can simply utilize them. Specs are at
     csharp-specs
     <http://msdn.microsoft.com/vstudio/nextgen/technology/csharpdownload.asp>
     and see C# overview
     <http://msdn.microsoft.com/vstudio/nextgen/technology/csharpintro.asp>.

  ·  Is a subset of C++ language but will force programmer to use obejct
     oriented programming.

  ·  Pure Object-oriented langauge but retains syntax of C++.

  ·  Remove all bad or confusing features of C++ in COOP, for e.g.
     multiple-inheritance, operator overloading, limit usage of
     pointers, etc...

  ·  Prevent writing "C" like programming in COOP, something which C++
     currently allows.  Delete all C features which are considered bad
     or redundant/duplicates, like printf, fprintf, malloc, struct, free
     etc..

  ·  No downward compatibility to "C" language.

  ·  Code written in COOP will be easy to maintain and is easily
     understandable/readable.

  ·  Code written in "COOP" will be re-usable (thru components, modules,
     objects).  Supports re-usable software components, thereby
     facilitating Rapid Application Development.

  ·  COOP is simple, robust, OOP, has bare mininum syntax (avoiding
     confusing, redundant, extra constructs of C++ for e.g remove struct
     and use class)

  Also borrow ideas from  -

  ·  Java - Sun Microsystem put lot of effort, and you can simply
     utilize that.

  ·  Connective C++ at  <http://www.quintessent.com/products/cc++>.

  2.  String Class Varieties

  The string class is the most vital object in programming, and string
  manipulations are most extensively used and they comprise of 20 to 60%
  of total code.  There are 3 variety of string classes. Ofcourse, you
  can build your own string class by simply inheriting from these string
  classes -

  ·  String class given in this document ``Appendix A String.h''


  ·  GNU string class

  ·  GNU C++ Library - Univ of Tech, Sydney
     <http://www.socs.uts.edu.au/doc/gnuinfo/libg++/libg++_18.html> and
     user's guide <http://www.socs.uts.edu.au/doc/gnuinfo/libg++>

  ·  mirror site Gesellschaft <http://www-
     aix.gsi.de/doc/gnu/libg++_18.html#SEC23> and user's guide
     <http://www.gsi.de/doc/gnu/libg++_toc.html>

  ·  mirror site Techno, Russia
     <http://www.techno.spb.ru/~xbatob/FAQ/GNU/libg++_19.html#SEC27> and
     user's guide
     <http://www.techno.spb.ru/~xbatob/FAQ/GNU/libg++_toc.html>

  ·  mirror site Univ of Utah
     <http://www.math.utah.edu/docs/info/libg++_19.html#SEC27> and
     user's guide <http://www.math.utah.edu/docs/info/libg++_toc.html>



  ·  Qt String class at  <http://doc.trolltech.com/qstring.html> mirror
     at <http://www.cs.berkeley.edu/~dmartin/qt/qstring.html>


  ·  If none of these alternatives are suitable, you can build your own
     string class.  You can start with one or more of the pre-built
     classes listed above (by using single or multiple inheritance.)

  2.1.  Multiple Inheritance - Sample Custom String class

  As mentioned above, you can build your own custom string class from
  the pre-built classes by single or multiple inheritance.  In this
  section we will build a sample custom string class by using multiple
  inheritance, inheriting from the GNU string class and the string class
  presented in Appendix H.

  Start by downloading the sample file 'string_multi.h' from ``'' . That
  file is reproduced below:



  ______________________________________________________________________
  // ******************************************************************
  // Sample program to demonstrate constructing your own string class
  // by deriving from the String class and stdlib's "string" class
  // ******************************************************************

  #ifndef __STRING_MULTI_H_
  #define __STRING_MULTI_H_

  #include <string>
  #include "String.h"

  // Important Notes: In C++ the constructors, destructors and copy
  //       operator are NOT inherited by the derived classes!!
  //       Hence, if the operators like =, + etc.. are defined in
  //       base class and those operators use the base class's contructors
  //       then you MUST define equivalent constructors in the derived
  //       class. See the sample given below where constructors mystring(),
  //       mystring(char[]) are defined.
  //
  //       Also when you use operator as in atmpstr + mstr, what you are really
  //       calling is atmpstr.operator+(mstr). The atmpstr is declared a mystring

  class mystring:public String, string
  {
          public:
                  mystring():String() {}  // These are needed for operator=, +
                  mystring(char bb[]):String(bb) {}  // These are needed for operator=, +
                  mystring(char bb[], int start, int slength):String(bb, start, slength) {}
                  mystring(int bb):String(bb) {}  // needed by operator+
                  mystring(unsigned long bb):String(bb) {}  // needed by operator+
                  mystring(long bb):String(bb) {}  // needed by operator+
                  mystring(float bb):String(bb) {}  // needed by operator+
                  mystring(double bb):String(bb) {}  // needed by operator+
                  mystring(const String & rhs):String(rhs) {}  // Copy Constructor needed by operator+
                  mystring(StringBuffer sb):String(sb) {}  // Java compatibility
                  mystring(int bb, bool dummy):String(bb, dummy) {}  // for StringBuffer class

                  int mystraa; // customizations of mystring
          private:
                  int mystrbb; // customizations of mystring
  };

  #endif // __STRING_MULTI_H_
  ______________________________________________________________________



  3.  Download String

  All the programs, examples are given in Appendix of this document.
  You can download as a single tar zip, the String class, libraries and
  example programs from

  ·  Go here and click on C++Programming howto.tar.gz file
     <http://www.aldev.8m.com>

  ·  Mirror sites :  <http://aldev.webjump.com>, angelfire
     <http://www.angelfire.com/nv/aldev>, geocities
     <http://www.geocities.com/alavoor/index.html>, virtualave
     <http://aldev.virtualave.net>, bizland <http://aldev.bizland.com>,
     theglobe <http://members.theglobe.com/aldev/index.html>, spree
     <http://members.spree.com/technology/aldev>, infoseek
     <http://homepages.infoseek.com/~aldev1/index.html>, bcity
     <http://www3.bcity.com/aldev>, 50megs <http://aldev.50megs.com>

  4.  Usage of String class

  To use String class, you should first refer to a sample program
  "example_String.cpp" given in ``Appendix A'' and the String class
  which is given in ``Appendix A''.

  The is a complete replacement for char and char * datatype.  You can
  use just like char and get much more functionalities.  You should link
  with the library 'libString.a' which you can build from the makefile
  given in ``Appendix A'' and copy the library to /usr/lib or /lib
  directory where all the "C++" libraries are located. To use the
  'libString.a' compile your programs like -

  ______________________________________________________________________
          g++ example.cpp -lString
  ______________________________________________________________________


  See illustration sample code as given below -

  ______________________________________________________________________
          String aa;

          aa = "Creating an Universe is very easy, similar to creating a baby human.";

          // You can use aa.val() like a 'char *' variable in programs
          for (unsigned long tmpii = 0; tmpii < aa.length(); tmpii++)
          {
                  //fprintf(stdout, "aa.val()[%ld]=%c ", tmpii, aa.val()[tmpii]);
                  fprintf(stdout, "aa[%ld]=%c ", tmpii, aa[tmpii]);
          }

          // Using pointers on 'char *' val ...
          for (char *tmpcc = aa.val(); *tmpcc != 0; tmpcc++)
          {
                  fprintf(stdout, "aa.val()=%c ", *tmpcc);
          }
  ______________________________________________________________________



  4.1.  Operators

  The provides these operators :-

  ·  Equal to ==

  ·  Not equal to !=

  ·  Assignment =

  ·  Add to itself and Assignment +=

  ·  String concatenation or addition +

     For example to use operators -



     ___________________________________________________________________
             String aa;
             String bb("Bill Clinton");

             aa = "put some value string";  // assignment operator
             aa += "add some more"; // Add to itself and assign operator
             aa = "My name is" + " Alavoor Vasudevan "; // string cat operator

             if (bb == "Bill Clinton")  // boolean equal to operator
                     cout << "bb is equal to 'Bill Clinton' " << endl;

             if (bb != "Al Gore")   // boolean 'not equal' to operator
                     cout << "bb is not equal to 'Al Gore'" << endl;
     ___________________________________________________________________



  4.2.  Functions

  The functions provided by String class has the same name as that of
  Java language's String class. The function names and the behaviour is
  exactly same as that of Java's String class. StringBuffer class is
  also provided.  This will facilitate portability of code between Java
  and C++ (you can cut and paste and do minimum changes to code).  The
  code from Java's function body can be copied into C++ member function
  body and with very mininum changes the code will compile under C++.
  Another advantage is that developers coding in both Java and C++ do
  not need to remember two different syntax or function names.

  For example to convert integer to string do -

  ______________________________________________________________________
          String  aa;

          aa = 34;  // The '=' operator will convert int to string
          cout << "The value of aa is : " << aa.val() << endl;

          aa = 234.878;  // The '=' operator will convert float to string
          cout << "The value of aa is : " << aa.val() << endl;

          aa = 34 + 234.878;
          cout << "The value of aa is : " << aa.val() << endl;
          // The output aa will be '268.878'

          // You must cast String to convert
          aa = (String) 34 + " Can create infinite number of universes!! " + 234.878;
          cout << "The value of aa is : " << aa.val() << endl;
          // The output aa will be '34 Can create infinite number of universes!! 234.878'
  ______________________________________________________________________



  Refer to ``Appendix A String.h'' for details about the String class
  function names. The same file String.h is reproduced here in next
  section.

  5.  String.h file

  In C++ (or any object oriented language), you just read the "class
  data-structure" (i.e. interface) to begin using that object.  You just
  need to understand the interface and not the implementation of the
  interface.  In case of String class, you just need to read and
  understand the String class in String.h file. You do not need to read
  the entire implementation (String.cpp) in order to use String class.
  The object oriented classes are real time saver and they very neatly
  hide the implementation.
  (In object oriented Java language there is the equivalent called
  'interface' , which hides the implementation details.)

  Given below is String.h file and see also ``Appendix A String.h''



  ______________________________________________________________________
  //
  // Author : Al Dev  Email: alavoor@yahoo.com
  // Use string class or String class
  //
  // To prevent memory leaks - a char class to manage character variables
  // Always prefer to use String or string class
  // instead of char[] or char *
  //

  #ifndef __STRING_H_
  #define __STRING_H_

  #include <iostream> // do not use iostream as program becomes bulky..
  #include <stdio.h> // for FILE and sprintf()
  #include <list.h> // for list

  const short INITIAL_SIZE =      50;
  const short NUMBER_LENGTH = 300;
  const int MAX_ISTREAM_SIZE = 2048;

  class StringBuffer;

  class String
  {
          public:
                  String();
                  String(const char bb[]);  // needed by operator+
                  String(const char bb[], int start, int slength); // subset of chars
                  String(int bb);  // needed by operator+
                  String(unsigned long bb);  // needed by operator+
                  String(long bb);  // needed by operator+
                  String(float bb);  // needed by operator+
                  String(double bb);  // needed by operator+
                  String(const String & rhs);  // Copy Constructor needed by operator+
                  String(StringBuffer sb);  // Java compatibility
                  String(int bb, bool dummy);  // for StringBuffer class
                  virtual ~String();  // Made virtual so that when base class is deleted
                                                          // then the derived class destructor is called.

                  char *val() {return sval;} // It is not safe to make sval public

                  // Functions below imitate Java language's String object
                  unsigned long length() { return strlen(sval); }
                  char charAt(int where);
                  void getChars(int sourceStart, int sourceEnd,
                                  char target[], int targetStart);
                  char* toCharArray();
                  char* getBytes();

                  bool equals(String str2); // See also == operator
                  bool equals(char *str2); // See also == operator
                  bool equalsIgnoreCase(String str2);

                  bool regionMatches(int startIndex, String str2,
                                  int str2StartIndex, int numChars);
                  bool regionMatches(bool ignoreCase, int startIndex,
                                  String str2, int str2StartIndex, int numChars);

                  String toUpperCase();
                  String toLowerCase();

                  bool startsWith(String str2);
                  bool startsWith(char *str2);

                  bool endsWith(String str2);
                  bool endsWith(char *str2);

                  int compareTo(String str2);
                  int compareTo(char *str2);
                  int compareToIgnoreCase(String str2);
                  int compareToIgnoreCase(char *str2);

                  int indexOf(char ch, int startIndex = 0);
                  int indexOf(char *str2, int startIndex = 0);
                  int indexOf(String str2, int startIndex = 0);

                  int lastIndexOf(char ch, int startIndex = 0);
                  int lastIndexOf(char *str2, int startIndex = 0);
                  int lastIndexOf(String str2, int startIndex = 0);

                  String substring(int startIndex, int endIndex = 0);
                  String replace(char original, char replacement);
                  String replace(char *original, char *replacement);

                  String trim(); // See also overloaded trim()

                  String concat(String str2);  // See also operator +
                  String concat(char *str2); // See also operator +

                  String reverse(); // See also overloaded reverse()
                  String deleteCharAt(int loc);
                  String deleteStr(int startIndex, int endIndex); // Java's "delete()"

                  String valueOf(char ch)
                          {char aa[2]; aa[0]=ch; aa[1]=0; return String(aa);}
                  String valueOf(char chars[]){ return String(chars);}
                  String valueOf(char chars[], int startIndex, int numChars);
                  String valueOf(bool tf)
                          {if (tf) return String("true"); else return String("false");}
                  String valueOf(int num){ return String(num);}
                  String valueOf(long num){ return String(num);}
                  String valueOf(float num) {return String(num);}
                  String valueOf(double num) {return String(num);}

                  // See also StringBuffer class in this file given below

                  // ---- End of Java like String object functions -----

                  //////////////////////////////////////////////////////
                  //              List of additonal functions not in java
                  //////////////////////////////////////////////////////
                  String ltrim();
                  void ltrim(bool dummy); // dummy to get different signature
                  String rtrim();
                  void rtrim(bool dummy); // dummy to get different signature

                  void chopall(char ch='\n'); // removes trailing character 'ch'
                  void chop(); // removes one trailing character

                  void roundf(float input_val, short precision);
                  void decompose_float(long *integral, long *fraction);

                  void roundd(double input_val, short precision);
                  void decompose_double(long *integral, long *fraction);

                  void explode(char *separator); // see also token() and overloaded explode()
                  String *explode(int & strcount, char separator = ' '); // see also token()
                  void implode(char *glue);
                  void join(char *glue);
                  String repeat(char *input, unsigned int multiplier);
                  String tr(char *from, char *to); // translate characters
                  String center(int padlength, char padchar = ' ');
                  String space(int number = 0, char padchar = ' ');
                  String xrange(char start, char end);
                  String compress(char *list = " ");
                  String left(int slength = 0, char padchar = ' ');
                  String right(int slength = 0, char padchar = ' ');
                  String overlay(char *newstr, int start = 0, int slength = 0, char padchar = ' ');

                  String at(char *regx); // matches first match of regx
                  String before(char *regx); // returns string before regx
                  String after(char *regx); // returns string after regx
                  String mid(int startIndex = 0, int length = 0);

                  bool isNull();
                  bool isInteger();
                  bool isInteger(int pos);
                  bool isNumeric();
                  bool isNumeric(int pos);
                  bool isEmpty();  // same as length() == 0
                  bool isUpperCase();
                  bool isUpperCase(int pos);
                  bool isLowerCase();
                  bool isLowerCase(int pos);
                  bool isWhiteSpace();
                  bool isWhiteSpace(int pos);
                  bool isBlackSpace();
                  bool isBlackSpace(int pos);
                  bool isAlpha();
                  bool isAlpha(int pos);
                  bool isAlphaNumeric();
                  bool isAlphaNumeric(int pos);
                  bool isPunct();
                  bool isPunct(int pos);
                  bool isPrintable();
                  bool isPrintable(int pos);
                  bool isHexDigit();
                  bool isHexDigit(int pos);
                  bool isCntrl();
                  bool isCntrl(int pos);
                  bool isGraph();
                  bool isGraph(int pos);

                  void clear();
                  int toInteger();
                  long parseLong();

                  double toDouble();
                  String token(char separator = ' '); // ref StringTokenizer, explode()
                  String crypt(char *original, char *salt);
                  String getline(FILE *infp = stdin); // see also putline()
                  //String getline(fstream *infp = stdin); // see also putline()

                  void putline(FILE *outfp = stdout); // see also getline()
                  //void putline(fstream *outfp = stdout); // see also getline()

                  void swap(String aa, String bb); // swap aa to bb
                  String *sort(String aa[]);  // sorts array of strings
                  String sort(int startIndex = 0, int length = 0);  // sorts characters inside a string
                  int freq(char ch); // returns the number of distinct, nonoverlapping matches
                  void Format(const char *fmt, ...);
                  String replace (int startIndex, int endIndex, String str);

                  void substring(int startIndex, int endIndex, bool dummy);
                  void reverse(bool dummy); // dummy to get different signature
                  String deleteCharAt(int loc, bool dummy);
                  String deleteStr(int startIndex, int endIndex, bool dummy);
                  void trim(bool dummy); // dummy to get different signature
                  String insert(int index, String str2);
                  String insert(int index, String str2, bool dummy);
                  String insert(int index, char ch);
                  String insert(int index, char ch, bool dummy);
                  String insert(char *newstr, int start = 0, int length = 0, char padchar = ' ');

                  String dump(); // Dump the string like 'od -c' (octal dump) does

                  // required by java's StringBuffer
                  void ensureCapacity(int capacity);
                  void setLength(int len);
                  void setCharAt(int where, char ch);

                  // required by java's Integer class, Long, Double classes
                  int parseInt(String ss) {return ss.toInteger();}
                  int parseInt(char *ss)
                          {String tmpstr(ss); return tmpstr.toInteger();}
                  long parseLong(String ss) {return ss.parseLong();}
                  long parseLong(char *ss)
                          {String tmpstr(ss); return tmpstr.parseLong();}
                  float floatValue() {return (float) toDouble(); }
                  double doubleValue() {return toDouble(); }

                  ///////////////////////////////////////////////
                  //              List of duplicate function names
                  ///////////////////////////////////////////////
                  // char * c_str() // use val()
                  // bool find();  // Use regionMatches()
                  // bool search();  // Use regionMatches()
                  // bool matches(); // Use regionMatches()
                  // int rindex(String str2, int startIndex = 0); Use lastIndexOf()
                  // String blanks(int slength);  // Use repeat()
                  // String append(String str2); // Use concat() or + operator
                  // String prepend(String str2);  // Use + operator. See also append()
                  // String split(char separator = ' ');  // Use token()
                  bool contains(char *str2, int startIndex = 0); // use indexOf()
                  // void empty(); Use is_empty()
                  // void vacuum(); Use clear()
                  // void erase(); Use clear()
                  // void zero(); Use clear()
                  // bool is_float(); Use is_numeric();
                  // bool is_decimal(); Use is_numeric();
                  // bool is_Digit(); Use is_numeric();
                  // float float_value(); Use toDouble();
                  // float tofloat(); Use toDouble();
                  // double double_value(); Use toDouble();
                  // double numeric_value(); Use toDouble();
                  // int int_value(); Use toInteger()
                  // int tonumber(); Use toInteger()
                  // String get(); Use substring() or val() but prefer java's substring
                  // String getFrom(); Use substring() or val() but prefer java's substring
                  // String head(int len); Use substring(0, len)
                  // String tail(int len); Use substring(length()-len, length())
                  // String cut(); Use deleteCharAt() or deleteStr()
                  // String cutFrom(); Use deleteCharAt() or deleteStr()
                  // String paste(); Use insert()
                  // String fill(); Use replace()
                  // char firstChar(); // Use substring(0, 1);
                  // char lastChar(); // Use substring(length()-1, length());
                  // String findNext(); Use token()

                  // begin();  iterator. Use operator [ii]
                  // end();  iterator. Use operator [ii]
                  // copy();  Use assignment =  operator, String aa = bb;
                  // clone();  Use assignment =  operator, String aa = bb;
                  // All Operators ...
                  String operator+ (const String & rhs);
                  friend String operator+ (const String & lhs, const String & rhs);

                  String& operator+= (const String & rhs); // using reference will be faster
                  String& operator= (const String & rhs); // using reference will be faster
                  bool operator== (const String & rhs); // using reference will be faster
                  bool operator== (const char *rhs);
                  bool operator!= (const String & rhs);
                  bool operator!= (const char *rhs);
                  char operator [] (unsigned long Index) const;
                  char& operator [] (unsigned long Index);
                  friend ostream &  operator<< (ostream & Out, const String & str2);
                  friend istream &  operator>> (istream & In, String & str2);

                  static  list<String>            explodeH;  // list head

          protected:
                  char *sval; // Not safe to make sval public
                  inline void verifyIndex(unsigned long index) const;
                  inline void verifyIndex(unsigned long index, char *aa) const;

                  void _str_cat(char bb[]);
                  void _str_cat(int bb);
                  void _str_cat(unsigned long bb);
                  void _str_cat(float bb);

          private:
                  // Note: All the private variables and functions begin
                  // with _ (underscore)

                  //static String *_global_String; // for use in add operator
                  //inline void _free_glob(String **aa);
                  void _str_cpy(char bb[]);
                  void _str_cpy(int bb); // itoa
                  void _str_cpy(unsigned long bb);
                  void _str_cpy(float bb); // itof

                  bool _equalto(const String & rhs, bool type = false);
                  bool _equalto(const char *rhs, bool type = false);
                  String *_pString;  // temporary pointer for internal use..
                  inline void _allocpString();
                  inline void _reverse();
                  inline void _deleteCharAt(int loc);
                  inline void _deleteStr(int startIndex, int endIndex);
                  inline void _trim();
                  inline void _ltrim();
                  inline void _rtrim();
                  inline void _substring(int startIndex, int endIndex);
  };

  // Imitate Java's StringBuffer object
  // This class is provided so that the Java code is
  // portable to C++, requiring minimum code changes
  // Note: While coding in C++ DO NOT use this class StringBuffer,
  // this is provided only for compiling code written in Java
  // which is cut/pasted inside C++ code.
  class StringBuffer: public String
  {
          public:
                  StringBuffer();
                  StringBuffer(int size);
                  StringBuffer(String str);
                  ~StringBuffer();

                  int capacity() {return strlen(sval);}
                  StringBuffer append(String str2)
                          { *this += str2; return *this;} // See also operator +
                  StringBuffer append(char *str2)
                          { *this += str2; return *this;} // See also operator +
                  StringBuffer append(int bb)
                          { *this += bb; return *this;} // See also operator +
                  StringBuffer append(unsigned long bb)
                          { *this += bb; return *this;} // See also operator +
                  StringBuffer append(float bb)
                          { *this += bb; return *this;} // See also operator +
                  StringBuffer append(double bb)
                          { *this += bb; return *this;} // See also operator +

                  StringBuffer insert(int index, String str2)
                          { return String::insert(index, str2, true);}

                  StringBuffer insert(int index, char ch)
                          { return String::insert(index, ch, true);}

                  StringBuffer reverse()
                          { String::reverse(true); return *this;}

                  // Java's "delete()". Cannot use name delete in C++
                  StringBuffer deleteStr(int startIndex, int endIndex)
                          { String::deleteStr(startIndex, endIndex, true); return *this;}
                  StringBuffer deleteCharAt(int loc)
                          { String::deleteCharAt(loc, true); return *this;}

                  StringBuffer substring(int startIndex, int endIndex = 0)
                          { String::substring(startIndex, endIndex, true); return *this;}
  };

  static String Integer("0"); // java's Integer.parseInt(String);
  static String Long("0"); // java's Long.parseLong(String);

  // Imitate java's Float class and Float.floatValue()
  // provided to compile java code in C++
  class Float: public String
  {
          public:
                  Float(String str);
                  Float valueOf(String str2) {return Float(str2);}
                  float floatValue() {return (float) toDouble(); }
  };

  // Imitate java's Double class and Double.doubleValue()
  // provided to compile java code in C++
  class Double: public String
  {
          public:
                  Double(String str);
                  Double valueOf(String str2) {return Double(str2);}
                  double doubleValue() {return toDouble(); }
  };

  // Imitate java's StringTokenizer class
  // provided to compile java code in C++ and vice-versa
  class StringTokenizer: public String
  {
          public:
                  StringTokenizer(String str);
                  StringTokenizer(String str, String delimiters);
                  StringTokenizer(String str, String delimiters, bool dflag);
                  ~StringTokenizer();

                  int     countTokens();
                  bool    hasMoreElements();
                  bool    hasMoreTokens();
                  String  nextElement(); // in java returns type 'Object'
                  String  nextToken();
                  String  nextToken(String delimiters);
          private:
                  int             mvCurrentPosition; // current index on string
                  int             mvTotalTokens;
                  int             mvRemainingTokens;
                  char *  mvpListOfDl; // list of delimiters
                  char *  mvpWorkStr; // temp work string
                  char *  mvpOrigStr; // original string passed
                  bool    mvDlFlag;  // delimiter flag
                  inline  void vPrepWorkStr(char *delimiters = NULL);
  };

  // Imitate java's StringReader class
  // provided to compile java code in C++
  class StringReader: public String
  {
          public:
                  StringReader(String str);
                  void close() {}  // close the stream
                  void mark(int readAheadLimit);
                  bool markSupported() {return true;} // tell whether this stream supports the mark() operation, which it does
                  int read();
                  int read(char cbuf[], int offset, int length);
                  bool ready() {return true;} // tell whether this stream is ready to read
                  void reset();
                  long skip(long ii);
          private:
                  unsigned long   _curpos;
                  unsigned long   _mark_pos;
  };

  // Imitate java's StringWriter class
  // provided to compile java code in C++
  class StringWriter: public String
  {
          public:
                  StringWriter();
                  StringWriter(int bufferSize);
                  void close() {clear();}
                  void flush() {clear();}
                  StringBuffer getBuffer() {return (StringBuffer) *this;}
                  String  toString() {return (String) *this;}
                  void write(int);
                  void write(String);
                  void write(char *str1);
                  void write(char str1[], int startIndex, int endIndex);
                  void write(String str1, int startIndex, int endIndex);
  };

  // Global variables are defined in String.cpp

  #endif // __STRING_H_
  ______________________________________________________________________



  6.  Renaming the String class



  6.1.  Case 1: Simple rename

  If you do not like the String class name then you can use "typedef" to
  rename the String class.

  In all the files where you do include String.h, insert these lines:

  ______________________________________________________________________
  // If you do not like the class name String, then you can rename using typedef
  typedef String StringSomethingElseIwant;

  // Your remaing code may be like this ....
  int main()
  {
          StringSomethingElseIwant aa_renstr;
          aa_renstr = "I renamed the String Class using typedef";

          .......etc...
  }
  ______________________________________________________________________


  See the example_String.cpp
  <http://www.angelfire.com/nv/aldev/cpphowto/example_String.cpp>.

  6.2.  Case 2: Resolve conflict

  If there is a conflict with another class-name having the same name,
  and you want to use both this class and conflicting class then you use
  this technique - in all the files where you do include String.h,
  insert these lines:

  ______________________________________________________________________
  #define  String  String_somethingelse_which_I_want
  #include "String.h"
  #undef String

  #include "ConflictingString.h"  // This also has String class...

  // All your code goes here...
  main()
  {
          String_somethingelse_which_I_want aa;
          String bb; // This string class from conflicting string class

          aa = " some sample string";
          bb = " another string abraka-dabraka";
          .......
  }
  ______________________________________________________________________


  The pre-processor will replace all literals of String to "String_some­
  thingelse_which_I_want" and immdiately undefines String.  After undef
  the conflicting string class header file is included which defines the
  "String" class.

  7.  File Class

  You would use the File class to manipulate the operating system files.
  This class is an imitation of Java's File class and will be very
  useful in C++ programming. Using this File class in C++ you can do if
  file exists() ?, if directory exists() ?, file length() and other
  functions.


  ·  C++ File class is at File.h
     <http://www.angelfire.com/nv/aldev/cpphowto/File.h> and File.cpp
     <http://www.angelfire.com/nv/aldev/cpphowto/File.cpp>


  ·  Java java.io.File class definition
     <http://java.sun.com/j2se/1.3/docs/api/java/io/File.html>

  ·  Quick Reference on File Class
     <http://unicornsrest.org/reference/java/qref11/java.io.File.html>

  ·  File Class summary  <http://www.idi.ntnu.no/~database/SIF8020/java-
     api/java.io.File.html>

  8.  C++ Zap (Delete) function

  The delete and new operators in C++ are much better than the malloc
  and free functions of C.  Consider using new and zap (delete function)
  instead of malloc and free as much as possible.

  To make delete operators even more cleaner, make a Zap() inline
  function. Define a zap() function like this:

  ______________________________________________________________________
  // Put an assert to check if x is NULL, this is to catch
  // program "logic" errors early. Even though delete works
  // fine with NULL by using assert you are actually catching
  // "bad code" very early

  // Defining Zap using templates
  // Use zap instead of delete as this will be very clean
  template <class T>
  inline void zap(T & x)
  {
          {assert(x != NULL);}
          delete x;
          x = NULL;
  }

  // In C++ the reason there are 2 forms of the delete operator is - because
  // there is no way for C++ to tell the difference between a pointer to
  // an object and a pointer to an array of objects. The delete operator
  // relies on the programmer using "[]" to tell the two apart.
  // Hence, we need to define zaparr function below.
  // To delete array of pointers
  template <class T>
  inline void zaparr(T & x)
  {
           {assert(x != NULL);}
       delete [] x;
       x = NULL;
  }
  ______________________________________________________________________



  The zap() function will delete the pointer and set it NULL.  This will
  ensure that even if multiple zap()'s are called on the same deleted
  pointer then the program will not crash. Please see the function
  zap_example() in example_String.cpp
  <http://www.angelfire.com/nv/aldev/cpphowto/example_String.cpp>.



  ______________________________________________________________________
          // See zap_example() in example_String.cpp
          zap(pFirstname);
          //zap(pFirstname); // no core dumps.  Because pFirstname is NULL now
          //zap(pFirstname); // no core dumps.  Because pFirstname is NULL now

          zap(pLastname);
          zap(pJobDescription);

          int *iiarray = new int[10];
          zaparr(iiarray);
  ______________________________________________________________________



  There is nothing magical about this, it just saves repetative code,
  saves typing time and makes programs more readable. The C++
  programmers often forget to reset the deleted pointer to NULL, and
  this causes annoying problems causing core dumps and crashes. The
  zap() takes care of this automatically.  Do not stick a typecast in
  the zap() function -- if something errors out on the above zap()
  function it likely has another error somewhere.

  Also ``my_malloc()'' , my_realloc() and my_free() should be used
  instead of malloc(), realloc() and free(), as they are much cleaner
  and have additional checks.  For an example, see the file "String.h"
  which is using the ``my_malloc()'' and my_free() functions.

  WARNING : Do not use free() to free memory allocated with 'new' or
  'delete' to free memory allocated with malloc. If you do, then results
  will be unpredictable.

  See the zap examples in example_String.cpp
  <http://www.angelfire.com/nv/aldev/cpphowto/example_String.cpp>.

  9.  Pointers are problems

  Pointers are not required for general purpose programming. In modern
  languages like Java there is no support for pointers (Java internally
  uses pointers). Pointers make the programs messy and programs using
  pointers are very hard to read.

  Avoid using pointers as much as possible and use references. Pointers
  are really a great pain. It is possible to write an application
  without using pointers.  You should pointers only in those cases where
  references will not work.

  A reference is an alias; when you create a reference, you initialize
  it with the name of another object, the target. From the moment on,
  the reference acts as an alternative name of the target, and anything
  you do to the reference is really done to the target.

  Syntax of References: Declare a reference by writing the type,
  followed by the reference operator (&), followed by the reference
  name. References MUST be initialized at the time of creation.  For
  example -

  ______________________________________________________________________
          int             weight;
          int     & rweight = weight;

          DOG             aa;
          DOG & rDogRef = aa;
  ______________________________________________________________________


  Do's of references -

  ·  Do use references to create an alias to an object

  ·  Do initialize all references

  ·  Do use references for high efficiency and performance of program.

  ·  Do use const to protect references and pointers whenever possible.

  Do not's of references -

  ·  IMPORTANT: Don't use references to NULL objects

  ·  Don't confuse the address of operator & with reference operator.
     The references are used in the declarations section (see Syntax of
     References above).

  ·  Don't try to reassign a reference

  ·  Don't use pointers if references will work

  ·  Don't return a reference to a local object

  ·  Don't pass by reference if the item referred to may go out of scope


  10.  Usage of my_malloc and my_free

  Try to avoid using malloc and realloc as much as possible and use new
  and ``zap''(delete). But sometimes you may need to use the "C" style
  memory allocations in "C++". Use the functions my_malloc() ,
  my_realloc() and my_free().  These functions do proper allocations and
  initialisations and try to prevent memory problems. Also these
  functions (in DEBUG mode) can keep track of memory allocated and print
  total memory usage before and after the program is run. This tells you
  if there are any memory leaks.

  The my_malloc and my_realloc is defined as below. It allocates little
  more memory (SAFE_MEM = 5) and initializes the space and if it cannot
  allocate it exits the program. The 'call_check(), remove_ptr()'
  functions are active only when DEBUG_MEM is defined in makefile and
  are assigned to ((void)0) i.e. NULL for non-debug production release.
  They enable the total-memory used tracing.



  ______________________________________________________________________
  void *local_my_malloc(size_t size, char fname[], int lineno)
  {
          size_t  tmpii = size + SAFE_MEM;
          void *aa = NULL;
          aa = (void *) malloc(tmpii);
          if (aa == NULL)
                  raise_error_exit(MALLOC, VOID_TYPE, fname, lineno);
          memset(aa, 0, tmpii);
          call_check(aa, tmpii, fname, lineno);
          return aa;
  }

  char *local_my_realloc(char *aa, size_t size, char fname[], int lineno)
  {
          remove_ptr(aa, fname, lineno);
          unsigned long tmpjj = 0;
          if (aa) // aa !=  NULL
                  tmpjj = strlen(aa);
          unsigned long tmpqq = size + SAFE_MEM;
          size_t  tmpii = sizeof (char) * (tmpqq);
          aa = (char *) realloc(aa, tmpii);
          if (aa == NULL)
                  raise_error_exit(REALLOC, CHAR_TYPE, fname, lineno);

          // do not memset memset(aa, 0, tmpii);
          aa[tmpqq-1] = 0;
          unsigned long kk = tmpjj;
          if (tmpjj > tmpqq)
                  kk = tmpqq;
          for ( ; kk < tmpqq; kk++)
                  aa[kk] = 0;
          call_check(aa, tmpii, fname, lineno);
          return aa;
  }
  ______________________________________________________________________


  See ``my_malloc.cpp''.  and the header file ``my_malloc.h''.  for full
  implementation of the my_malloc program.

  An example on usage of my_malloc and my_free as below:

  ______________________________________________________________________
          char    *aa;
          int     *bb;
          float   *cc;
          aa = (char *) my_malloc(sizeof(char)* 214);
          bb = (int *) my_malloc(sizeof(int) * 10);
          cc = (float *) my_malloc(sizeof(int) * 20);

          aa = my_realloc(aa, sizeof(char) * 34);
          bb = my_realloc(bb, sizeof(int) * 14);
          cc = my_realloc(cc, sizeof(float) * 10);
  ______________________________________________________________________


  Note that in my_realloc you do not need to cast the datatype as the
  variable itself is passed and correct my_realloc is called which
  returns the proper datatype pointer. The my_realloc has overloaded
  functions for char*, int* and float*.

  10.1.  Garbage Collector for C++

  In C/C++ Garbage Collection is not a standard feature and hence
  allocating and freeing storage explicitly is difficult, complicated
  and is error-prone.  The Garbage Collection (GC) is not part of the
  C++ standard because there are just so many ways how one could
  implement it; there are many GC techniques, and deciding to use a
  particular one would not be good for certain programs. Computer
  scientists had designed many GC algorithms, each one of them catering
  to a particular problem domain.  There is no one single generic GC
  which will tackle all the problem domains.  As a consequence, GC is
  not part of C++ standard, they just left it out.  Still, you always
  have the choice of many freely available C++ libraries that do the job
  for you.

  Visit the C++ Garbage Collection
  <http://www.xanalys.com/software_tools/mm/glossary/g.html#garbage.collection>
  and Memory management <http://www.xanalys.com/software_tools/mm> site.

  11.  Debug files

  To debug any C++ or C programs include the file ``debug.h'' and in
  your 'Makefile' define DEBUG_STR, DEBUG_PRT, DEBUG_MEM to turn on the
  traces from the debug.h functions.  When you remove the '-DDEBUG_STR'
  etc.. then the debug function calls are set to ((void)0) i.e. NULL,
  hence it has no impact on final production release version of project.
  You can generously use the debug functions in your programs and it
  will not increase the size of production executable.

  See the file ``debug.cpp'' for implementation of debug routines.  And
  see the file ``my_malloc.cpp'' for sample which uses debug.h and debug
  functions.

  See the sample ``Makefile'' .

  12.  Java like API

  Visit the following sites for Java like API for C++

  ·  Java utils in C++  <http://www.pulsar.org/users/ej/archive/oop>

  ·  PhD Thesis book Java API in C++
     <http://www.pulsar.org/archive/phd/ejphd>

  13.  IDE tools for C++

  The following IDE tools (Integrated Development Environment) are
  available for C++:

  ·  KDE Kdevelop <http://www.kdevelop.org>

  ·  Blatura site C++ Tools
     <http://home.xnet.com/~blatura/linapp6.html#tools>

  ·  Amulet Amulet
     <http://www.cs.cmu.edu/afs/cs.cmu.edu/project/amulet/www>

  ·  App Dev suite Angoss <http://www.angoss.com/sw/home.htm>

  ·  Make replacement Brass <http://wsd.iitb.fhg.de/~kir/brashome/>

  ·  S/W product metrics CCC <http://www.fste.ac.cowan.edu.au/~tlittlef>

  ·  Project mgmt, edit, compile, debug C-Forge
     <http://www.codeforge.com>

  ·  Dev environment Code Crusader
     <http://www.cco.caltech.edu/~jafl/jx/progs.html>


  ·  Graphic gdb Code Medic <http://www.cco.caltech.edu/~glenn/medic/>

  ·  Code analysis CodeWizard
     <http://www.parasoft.com/wizard/index.html>

  ·  Gen HTML, LaTex for C++ cod Doc C++
     <http://www.zib.de/Visual/software/doc++/index.html>

  ·  GUI toolkit openGL Ftk <http://fltk.easysw.com/>

  ·  C++ and Java IDE GLG IDE <http://www.genlogic.com>

  ·  HP IDE HP Eloquence <http://www.hp-eloquence.com/sales/info.html>

  ·  IDE C++, Java, Pascal RHIDE <http://www.tu-
     chemnitz.de/~sho/rho/rhide.html>

  ·  IDE for C++, Java SNiff <http://www.takefive.com/>

  ·  IDE for C++, Java Wipeout <http://www.softwarebuero.de/wipeout-
     eng.html>

  ·  X-based dev env XWPE <http://www.rpi.edu/~payned/xwpe>

  14.  C++ Online Textbooks and Docs


  ·  "C++ Annotations" online book main site:Annotations
     <http://www.icce.rug.nl/docs/cplusplus> better site : mirror-site
     <http://www.physik.tu-muenchen.de/cip-
     tutorials/Documents/c++-annotations/cplusplus.html>

  ·  "Teach Yourself C++ in 21 days" online textbook Teach C++
     <http://guides.oernii.sk/c++/index.htm>

  ·  "C++ Online" Textbook C++ Bruce Eckel
     <http://www.bruceeckel.com/DownloadSites>

  ·  C++ Open books: Panorama
     <http://www.softpanorama.org/Bookshelf/cpp.shtml> and click on Open
     Books.

  ·  "Who's Afraid of C++?" online textbook Steveheller
     <http://www.steveheller.com/whos>

  ·  "Introduction to Object Oriented Programming" an ebook C++ OOP
     <http://www.gnacademy.org/uu-gna/text/cc/Tutorial/tutorial.html>

  ·  C++ in Hypertext C++ Hypertext
     <http://cs.nmhu.edu/personal/curtis/cs1htmlfiles/Cs1text.htm>

  ·  Object Oriented Systems OOP article
     <http://www.javaworld.com/javaworld/jw-07-1999/jw-07-toolbox_p.html>


  ·  Porting C++ to Java PortingC
     <http://www.ibm.com/java/education/portingc>

  ·  C/C++ Journals UtahJournals
     <http://www.math.utah.edu/pub/tex/bib/toc/cccuj.html>

  ·  Yahoo C++ category site CCyahoo
     <http://dir.yahoo.com/Computers_and_Internet/Programming_Languages/C_and_C__/C__>

  ·  C Library Reference Guidec_guide
     <http://www.acm.uiuc.edu/webmonkeys/book/c_guide/index.html>
  ·  Online textbooks C++/Java FreeLib
     <http://www.informit.com/free_library>

  Java books which will be useful for C++ programmers:

  ·  Great Web reference site WebRef
     <http://www.webreference.com/index2.html>

  ·  Many java books JBooks <http://freewarejava.com/books/index.shtml>

  ·  Intro to Java V3.0 JavaNotes <http://math.hws.edu/javanotes> mirror
     JavaNotes
     <http://matrix.mvhs.fuhsd.org/~deruiter/javanotes3/contents.html>

  ·  Web Library:  <http://www.itlibrary.com>

  ·  Intermediate Level Java book:  <http://www.bruceeckel.com>

  ·  Thinking in Java : Thinking C++
     <http://www.sce.carleton.ca/netmanage/java/thinking/toc.html>

  ·  John Hopkins Univ - Java resources Hall
     <http://www.apl.jhu.edu/~hall/java>

  ·  online java tutorial Chortle
     <http://chortle.ccsu.ctstateu.edu/cs151/cs151java.html>

  ·  Practical guide for Java SunBooks
     <http://java.sun.com/docs/books/tutorial/index.html>

  ·  Java Soton <http://journals.ecs.soton.ac.uk/java/tutorial/TOC.html>

  15.  C++ Coding Standards

  Coding standard is very essential for readability and maitainence of
  programs. And it also greatly inproves the productivity of the
  programmer. The GNU C++ compiler must enforce coding discipline. The
  following is suggested - inside class definition:

  ·  All public variables must begin with m like mFooVar.  The m stands
     for member.

  ·  All protected variables must begin with mt, like mtFooVar and
     methods with t, like tFooNum().  The t stands for protected.

  ·  All private variables must begin with mv, like mvFooVar and methods
     with v, like vFooLone(). The v stands for private.

  ·  All public, protected and private variables must begin with
     uppercase after m like F in mFooVar.

  ·  All pointer variables must be prefixed with p, like

  ·  Public variables mpFooVar  and methods like FooNum()

  ·  Protected variables mtpFooVar and methods with t like tFooNum()

  ·  Private variables mvpFooVar and methods with v like vFooNum()

     The compiler should generate error if the code does not follow
     above standard.  The C++ compiler can provide a flag option to
     bypass strict coding standard to compile old source code, and for
     all new code being developed will follow the uniform world-wide
     coding standard.


  In the sample code given below t stands for protected, v stands for
  private, m stands for member-variable and p stands for pointer.

  ______________________________________________________________________
  class SomeFunMuncho
  {
          public:
                  int     mTempZimboniMacho; // Only temporary variables should be public as per OOP
                  float   *mpTempArrayNumbers;
                  int     HandleError();
                  float   getBonyBox();  // Public accessor as per OOP design
                  float   setBonyBox();  // Public accessor as per OOP design
          protected:
                  float   mtBonyBox;
                  int     *mtpBonyHands;
                  char    *tHandsFull();
                  int     tGetNumbers();
          private:
                  float   mvJustDoIt;
                  char    mvFirstName[30];
                  int     *mvpTotalValue;
                  char    *vSubmitBars();
                  int     vGetNumbers();
  };
  ______________________________________________________________________


  When your program grows by millions of lines of code, then you will
  greatly appreciate the naming convention as above. The readability of
  code improves, because just by looking at the variable name like
  mvFirstName you can tell that it is member of a class and is a private
  variable.

  Visit the C++ Coding Standards URLs

  ·  C++ FAQ Lite - Coding standards  <http://new-
     brunswick.net/workshop/c++/faq/coding-standards.html>

  ·  Rice university coding standard
     <http://www.cs.rice.edu/~dwallach/CPlusPlusStyle.html>

  ·  Identifiers to avoid in C++ Programs
     <http://oakroadsystems.com/tech/cppredef.htm>

  ·  Coding standards from Possibility
     <http://www.possibility.com/Cpp/CppCodingStandard.html> and mirror
     site
     <http://www.cs.umd.edu/users/cml/cstyle/CppCodingStandard.html>

  ·  Coding standards for Java and C++ from Ambysoft
     <http://www.ambysoft.com/javaCodingStandards.html>

  ·  Rules and recommendations
     <http://www.cs.umd.edu/users/cml/cstyle/>

  ·  Indent and annotate
     <http://www.cs.umd.edu/users/cml/cstyle/indhill-annot.html>

  ·  Elemental rules  <http://www.cs.umd.edu/users/cml/cstyle/Ellemtel-
     rules.html>

  ·  C++ style doc  <http://www.cs.umd.edu/users/cml/cstyle/Wildfire-
     C++Style.html>

  ·  C++ Coding Standards by Brett Scolcum
     <http://www.skypoint.com/~slocum/prog/cppstds.html>
  ·  Logikos C++ Coding Standards
     <http://www.logikos.com/standards/cpp_std.html>

  ·  NRad C++ coding standards
     <http://cadswes.colorado.edu/~billo/standards/nrad>

  ·  BEJUG C++ coding standards  <http://www.meurrens.org/ip-
     Links/java/joodcs/ToddHoff.html>

     See also

  ·  For rapid navigation with ctags Vim color text editor
     <http://metalab.unc.edu/LDP/HOWTO/Vim-HOWTO.html>

  ·  To improve productivity see C++ Beautifier HOWTO
     <http://metalab.unc.edu/LDP/HOWTO/C-C++Beautifier-HOWTO.html>

  16.  C++ Online Docs

  There are MORE THAN ONE MILLION online articles/textbooks/reference
  guides on C++ language. That is because C++ is used extensively for a
  very long period of time.  You can find them using the Internet search
  engines like Yahoo, Lycos, Excite etc..

  Visit the following C++ sites :-


  ·  C++ STL basic string class
     <http://www.sgi.com/Technology/STL/basic_string.html>

  ·  See the section ``STL References''



  ·  C++ Crash-proof site
     <http://www.troubleshooters.com/codecorn/crashprf.htm>

  ·  C++ Memory site
     <http://www.troubleshooters.com/codecorn/memleak.htm>



  ·  GNU Main site  <http://www.gnu.org> and gnu C++ site at
     <http://www.gnu.org/software/gcc/gcc.html>

  ·  GNU C++ Library - socs
     <http://www.socs.uts.edu.au/doc/gnuinfo/libg++/libg++_18.html>

  ·  GNU C++ Library - gsi  <http://www.gsi.de/doc/gnu/libg++_toc.html>

  ·  GNU C++ Library - techno
     <http://www.techno.spb.ru/~xbatob/FAQ/GNU/libg++_toc.html>

  ·  GNU C++ Library - utah
     <http://www.math.utah.edu/docs/info/libg++_toc.html>

  ·  AS University C++ Standard String class
     <http://www.eas.asu.edu/~cse200/outline>



  ·  Java JString for C++
     <http://www.mike95.com/c_plusplus/classes/JString/JString_cpp.asp>

  ·  C++ Language Reference  <http://www.msoe.edu/~tritt/cpplang.html>

  ·  C++ Program examples and samples
     <http://www.msoe.edu/~tritt/cpp/examples.html>

  ·  Neil's C++ stuff  <http://www.cyclone7.com/cpp>

  Internet has vast amounts of documentation on C++. Visit the search
  engines like Yahoo, Lycos, Infoseek, Excite. Type in the keywords .
  You can narrow down the search criteria by clicking on Advanced search
  and select search by exact phrase


  ·  <http://www.yahoo.com>

  ·  <http://www.lycos.com>

  ·  <http://www.infoseek.com>

  ·  <http://www.excite.com>

  ·  <http://www.mamma.com>

  16.1.  C++ Tutorials

  There are many on-line tutorials available on internet. Type 'C++
  tutorials' in the search engine.

  ·  C++ Tutorial  <http://www.xploiter.com/programming/c/index.shtml>

  ·  C++ Tutorial IISc, India
     <http://www.csa.iisc.ernet.in/Documentation/Tutorials/StyleGuides/c++-style.html>

  ·  C++ Tutorial Brown Univ
     <http://wilma.cs.brown.edu/courses/cs032/resources/C++tutorial.html>

  ·  C++ Tutorial
     <http://home.msuiit.edu.ph/~ddd/tutorials/cpp/cpplist.htm>

  ·  C++ Tutorial IOstreams
     <http://osiris.sunderland.ac.uk/~cs0pdu/pub/com365/Sched3/iocpp.html>


  16.2.  Useful links

  Bird's eye view of C++ URLs (about 153 url links)
  <http://www.enteract.com/~bradapp/links/cplusplus-links.html>

  This  <URL: http://www.snippets.org> portable C code contains over 360
  files.

  16.3.  C++ Quick-Reference

  Type 'C++ Reference' in the search engine.

  ·  C++ quick ref  <http://www.cs.jcu.edu.au/~david/C++SYNTAX.html>

  ·  C++ Standard Library Quick Reference
     <http://www.halpernwightsoftware.com/stdlib-scratch/quickref.html>

  ·  C++ STL from halper  <http://www.halpernwightsoftware.com/stdlib-
     scratch/quickref.html>

  16.4.  C++ Usenet Newsgroups


  ·  C++ newsgroups : comp.lang.c++.announce

  ·  C++ newsgroups : comp.lang.c++.*

  ·  C++ newsgroups :  <http://marshall-cline.home.att.net/cpp-faq-lite>

  17.  Memory Tools

  Use the following memory debugging tools

  ·  The MPatrol is a very powerful memory debugging tool.  It is at
     <http://www.cbmamiga.demon.co.uk/mpatrol> and at
     <http://www.rpmfind.net> go here and search mpatrol.  If you are
     using linux then you must download the mpatrol*.src.rpm file from
     the rpmfind.net. To update the mpatrol*.src.rpm to latest version,
     you can use the old mpatrol.spec file and latest mpatrol*.tar.gz
     file to rebuild new *.src.rpm.

  ·  On linux contrib cdrom see mem_test*.rpm package and at
     <http://www.rpmfind.net> go here and search mem_test.

  ·  On linux cdrom see ElectricFence*.rpm package and at
     <http://www.rpmfind.net> go here and search electricfence.

  ·  Purify Tool from Rational Software Corp  <http://www.rational.com>

  ·  Insure++ Tool from Parasoft Corp  <http://www.parasoft.com>

  ·  Linux Tools at  <http://www.xnet.com/~blatura/linapp6.html#tools>

  ·  Search the Internet engines like Yahoo, Lycos, Excite, Mamma.com
     for keyword "Linux memory debugging tools".

  18.  Related URLs

  You MUST use a color editor like 'Vim' (Vi improved) while coding in
  C++. Color editors greatly increase your productivity. Visit the URL
  for Vim howto below.

  Visit following locators which are related to C, C++ -

  ·  Vim color text editor for C++, C
     <http://metalab.unc.edu/LDP/HOWTO/Vim-HOWTO.html>

  ·  C++ Beautifier HOWTO  <http://metalab.unc.edu/LDP/HOWTO/C-
     C++Beautifier-HOWTO.html>

  ·  Source code control system for C++ programs (CVS HOWTO)
     <http://metalab.unc.edu/LDP/HOWTO/CVS-HOWTO.html>

  ·  Linux goodies  <http://www.aldev.8m.com> and mirrors at webjump
     <http://aldev.webjump.com>, angelfire
     <http://www.angelfire.com/nv/aldev>, geocities
     <http://www.geocities.com/alavoor/index.html>, virtualave
     <http://aldev.virtualave.net>, bizland <http://aldev.bizland.com>,
     theglobe <http://members.theglobe.com/aldev/index.html>, spree
     <http://members.spree.com/technology/aldev>, infoseek
     <http://homepages.infoseek.com/~aldev1/index.html>, bcity
     <http://www3.bcity.com/aldev>, 50megs <http://aldev.50megs.com>

  19.  C++ Scripting Languages


  19.1.  PIKE (C/C++ Scripting Language)

  The major disadvantage of C++ is that you must recompile and link the
  object files to create a executable anytime you make a small change.

  The scripting language like PIKE eliminates the linking and re-
  compiling and will really speed up the development process.

  As memory (RAM) prices are dropping and CPU speeds are increasing,
  scripting language like PIKE will EXPLODE in popularity. PIKE will
  become most widely used scripting language as it is object oriented
  and it's syntax is very identical to that of C++ language.

  Programming productivity will increase by five times by using the Pike
  C++ scripting language. And Pike is very useful for 'proof of concept'
  and developing prototypes rapidly.

  The Pike is at   <http://pike.roxen.com> and at
  <http://www.roxen.com>.

  The Roxen Web server is completely written in Pike, which demonstrates
  how powerful Pike is. Pike runs much faster than Java for some
  operations and is quite efficient in using memory resources.

  19.2.  PHP (C++ Scripting Language)

  PHP is hypertext-preprocessor scripting language and is very rapidly
  evolving getting object oriented features. It has the "class" keyword
  through which it tries to implement object oriented scripting. May be
  in near future PHP will mature rapidly to become a robust scripting
  language for object oriented projects.  In future it will tackle both
  the web applications and general purpose applications.  Why have
  different scripting languages for web and general applications,
  instead use just PHP for both. PHP is at
  <http://www.linuxdoc.org/HOWTO/PHP-HOWTO.html>.

  20.  Templates


  ·  <http://babbage.cs.qc.edu/STL_Docs/templates.htm> Mirror at:
     <http://www.mike95.com/c_plusplus/tutorial/templates>



  ·  This tells about #pragma template : -
     <http://www.dgp.toronto.edu/people/JamesStewart/270/9697f/notes/Nov25-tut.html>



  ·  Very GOOD site: <http://www.cplusplus.com/doc/tutorial/tut5-1.html>
     <http://www.cplusplus.com/doc/tutorial>



  ·  For certification of C++: goto  <http://examware.com> and click on
     "Tutorials" and then C/C++ button



  ·  C++ Open books:  <http://www.softpanorama.org/Lang/cpp.shtml> and
     click on tutorials



  ·  Templates tutorial :
     <http://www.infosys.tuwien.ac.at/Research/Component/tutorial/prwmain.htm>

  21.  STL References

  Please visit the following sites for STL -

  ·  Very good intro to iterators
     <http://www.cs.trinity.edu/~joldham/1321/lectures/iterators/>

  ·  CMU univ
     <http://www.cs.cmu.edu/afs/andrew/course/15/129/Cpp/10-STL/>

  ·  Intro to STL SGI
     <http://www.sgi.com/Technology/STL/stl_introduction.html>

  ·  Mumits STL Newbie guide
     <http://www.xraylith.wisc.edu/~khan/software/stl/STL.newbie.html>
     Mumit Khan's informative STL introduction is full of examples
     <http://abel.hive.no/C++/STL/stlnew.html>

  ·  ObjectSpace examples: ObjectSpace has contributed over 300 examples
     to the public domain and these are a very good start for beginners.
     <ftp://butler.hpl.hp.com/stl/examples.zip>

  ·  Joseph Y. Laurino's STL page.
     <http://weber.u.washington.edu/~bytewave/bytewave_stl.html>

  ·  Musser's STL docs and examples. Very nice.
     <http://www.cs.rpi.edu/~musser/stl.html>

  ·  STL Newbie home site.
     <http://www.xraylith.wisc.edu/~khan/software/stl/STL.newbie.html>

  ·  Marian Corcoran's STL FAQ.  <ftp://butler.hpl.hp.com/stl/stl.faq>

  STL Tutorial:

  ·  The best doc on tutorial -
     <http://www.decompile.com/html/tut.html> Mirror:  <http://mip.ups-
     tlse.fr/~grundman/stl-tutorial/tutorial.html>

  ·  very good -  <http://www.yrl.co.uk/~phil/stl/stl.htmlx>

  ·  C++ Standard Template LibraryAnother great tutorial, by Mark Sebern
     <http://www.msoe.edu/eecs/cese/resources/stl/index.htm>

  ·  By Jak Kirman: <http://129.187.112.56/Misc/Computer/stl-
     tutorial/tutorial_9.html> Mirrors :
     <http://www.cs.brown.edu/people/jak/proglang/cpp/stltut/tut.html>
     <http://saturn.math.uaa.alaska.edu/~afjhj/cs403/stl/tutorial.html>

  ·  Technical University Vienna by Johannes Weidl
     <http://dnaugler.cs.semo.edu/tutorials/stl> mirror
     <http://www.infosys.tuwien.ac.at/Research/Component/tutorial/prwmain.htm>

  ·  Colorful Tutorial
     <http://www.codeproject.com/cpp/stlintroduction.asp>

  Ready-made Components for use with the STL

  ·  STL components Collected by Boris Fomitche
     <http://www.metabyte.com/~fbp/stl/components.html>

  Main STL sites -

  ·  C++ STL from SGI  <http://www.sgi.com/Technology/STL>

  ·  C++ STL from RPI univ
     <http://www.cs.rpi.edu/projects/STL/htdocs/stl.html>

  ·  Lycos C++ STL site
     <http://dir.lycos.com/Computers/Programming/Languages/C%2B%2B/Class_Libraries/STL>
  ·  STL for C++ Programmers
     <http://userwww.econ.hvu.nl/~ammeraal/stlcpp.html>

  ·  C++ STL from halper  <http://www.halpernwightsoftware.com/stdlib-
     scratch/quickref.html>

  21.1.  Overview of the STL

  The STL offers the programmer a number of useful data structures and
  algorithms. It is made up the following components.


  ·  Containers. There are two types:

  ·  Sequential. This group comprises the vector, list and dequeue
     types.

  ·  Sorted Associative. This group comprises the set, map, multiset and
     multimap types.



  ·  Iterators. These are pointer like objects that allow the user to
     step through the contents of a container.


  ·  Generic Algorithms. The STL provides a wide range of efficently
     implemented standard algorithms (for example find, sort and merge)
     that work with the container types. (Some of the containers have
     special purpose implementations of these algorithms as member
     functions.)


  ·  Function Objects. A function object is an instance of a class that
     provides a definition of operator(). This means that you can use
     such an object like a function.


  ·  Adaptors. The STL provides

  ·  Container adaptors that allow the user to use, say, a vector as the
     basis of a stack.

  ·  Function adaptors that allow the user to construct new function
     objects from existing function objects.



  ·  Allocators. Every STL container class uses an Allocator class to
     hold information about the memory model the program is using. I
     shall totally ignore this aspect of the STL.

  I will be considering the use of the vector, list, set and map
  containers. To make use of these containers you have to be able to use
  iterators so I shall have something to say about STL iterators. Using
  the set and map containers can mean having to supply a simple function
  object to the instantiation so I shall also have something to say
  about function objects. I will only briefly mention the algorithms
  supplied by the STL. I will not mention adaptors at all.

  I have taken liberties with some of the types of function arguments --
  for example most of the integer arguments referred to in what follows
  actually have type size_type which is typedef'ed to an appropriate
  basic type depending on the allocation model being used. If you want
  to see the true signatures of the various functions discussed have a
  look at the Working Paper or the header files.
  There are a number of utility classes supplied with the STL. The only
  one of importance to us is the pair class. This has the following
  definition:


  ______________________________________________________________________
  template<class T1, class T2>
  class pair {
  public:
  T1 first;
  T2 second;
  pair(const T1& a, const T2& b) : first(a), second(b) {}

  };
  ______________________________________________________________________



  and there is a convenient function make_pair with signature:


  ______________________________________________________________________
  pair<T1,T2> make_pair(const T1& f, const T2&,s)
  ______________________________________________________________________



  as well as implementations of operator== and operator < . There is
  nothing complicated about this template class and you should be able
  to use it without further guidance. To use it #include the header file
  pair.h. It crops up in a number of places but particularly when using
  the set and map classes.

  21.2.  Header Files

  To use the various bits of the STL you have to #include the
  appropriate header files. These may differ slightly from compiler to
  compiler but for g++ the ones of interest are:


  ·  vector.h for the vector type.

  ·  list.h for the list type.

  ·  set.h for the set type.

  ·  map.h for the map type.

  ·  algo.h for access to the generic algorithms.

  If you don't want to remember which is which you could just use stl.h
  which includes all the above (and all the other header files of the
  STL as well).

  21.3.  The Container Classes Interface

  The container classes have many member functions that have the same
  names. These functions provide the same (or very similar) services for
  each of the classes (though, of course, the implementations will be
  different). The following table lists the functions that we shall
  consider in more detail. A star opposite a function name indicates
  that the container type heading the column provides a member function
  of that name.



           Operation    Purpose                        Vector
           _____________________________________________________________
                  ==    comparison                     *
                    <    comparison                     *
                begin    iterator                       *
                  end    iterator                       *
                 size    no. of elements                *
                empty    is container empty             *
                front    first element                  *
                 back    last element                   *
                 [ ]     element access/modification    *
               insert    insert element(s)              *
            push_back    insert new last element        *
           push_front    insert new first element
                erase    remove element(s)              *
             pop_back    remove last element            *
            pop_front    remove last element


                        Container Class Interface
  If the following discussion leaves something unclear (and it will) you
  can always write a small test program to investigate how some function
  or feature behaves.

  21.4.  Vectors

  A vector is an array like container that improves on the C++ array
  types. In particular it is not neccessary to know how big you want the
  vector to be when you declare it, you can add new elements to the end
  of a vector using the push_back function. (In fact the insert function
  allows you insert new elements at any position of the vector, but this
  is a very inefficent operation -- if you need to do this often
  consider using a list instead).

  21.4.1.  Constructing Vectors

  vector is a class template so that when declaring a vector object you
  have to state the type of the objects the vector is to contain. For
  example the following code fragment


  ______________________________________________________________________
  vector<int> v1;
  vector<string> v2;
  vector<FiniteAutomaton> v3;
  ______________________________________________________________________



  declares that v1 is a vector that holds integers, v2 a vector that
  holds strings and v3 holds objects of type FiniteAutomaton (presumably
  an user defined class type). These declarations do not say anything
  about how large the vectors are to be (implementations will use a
  default starting size) and you can grow them to as large as you
  require.

  You can give an inital size to a vector by using a declaration like


  ______________________________________________________________________
  vector<char> v4(26);
  ______________________________________________________________________



  which says that v4 is to be vector of characters that initially has
  room for 26 characters. There is also a way to initailise a vector's
  elements. The declaration


  ______________________________________________________________________
  vector<float> v5(100,1.0);
  ______________________________________________________________________



  says that v5 is a vector of 100 floating point numbers each of which
  has been initialised to 1.0.

  21.4.2.  Checking Up on Your Vector

  Once you have created a vector you can find out the current number of
  elements it contains by using the size function. This function takes
  no arguments and returns an integer (strictly a value of type
  size_type, but this gets converted to an integer) which says how many
  elements there are in the vector. What will be printed out by the
  following small program?


  ______________________________________________________________________
  <vector-size.cc>=
  #include <iostream.h>
  #include <vector.h>

  void main()
  {
    vector<int> v1;
    vector<int> v2(10);
    vector<int> v3(10,7);

    cout << "v1.size() returns " << v1.size() << endl;
    cout << "v2.size() returns " << v2.size() << endl;
    cout << "v3.size() returns " << v3.size() << endl;
  }
  ______________________________________________________________________



  To check on wether your vector is empty or not you can use the empty
  function. This takes no arguments and returns a boolean value, true if
  the vector is empty, false if it is not empty. What will be printed
  out by the following small program (true prints as 1 and false prints
  as 0)?



  ______________________________________________________________________
  <vector-empty.cc>=
  #include <iostream.h>
  #include <vector.h>

  void main()
  {
    vector<int> v1;
    vector<int> v2(10);
    vector<int> v3(10,7);

    cout << "v1.empty() has value " << v1.empty() << endl;
    cout << "v2.empty() has value " << v2.empty() << endl;
    cout << "v3.empty() has value " << v3.empty() << endl;
  }
  ______________________________________________________________________



  21.4.3.  Accessing Elements of a Vector

  You can access a vector's elements using operator[]. Thus, if you
  wanted to print out all the elements in a vector you could use code
  like


  ______________________________________________________________________
  vector<int> v;
  // ...
  for (int i=0; i<v.size(); i++)
       cout << v[i];
  ______________________________________________________________________



  (which is very similar to what you might write for a builtin array).

  You can also use operator[] to set the values of the elements of a
  vector.


  ______________________________________________________________________
  vector<int> v;
  // ...
  for (int i=0; i<v.size(); i++)
        v[i] = 2*i;
  ______________________________________________________________________



  The function front gives access to the first element of the vector.


  ______________________________________________________________________
  vector<char> v(10,'a');
  // ...
  char ch = v.front();
  ______________________________________________________________________



  You can also change the first element using front.



  ______________________________________________________________________
  vector<char> v(10,'a');
  // ...
  v.front() = 'b';
  ______________________________________________________________________



  The function back works the same as front but for the last element of
  the vector.


  ______________________________________________________________________
  vector<char> v(10,'z');
  // ...
  char last = v.back();
  v.back() = 'a';
  ______________________________________________________________________



  Here is a simple example of the use of [].


  ______________________________________________________________________
  <vector-access.cc>=
  #include <vector.h>
  #include <iostream.h>

  void main()
  {
    vector<int> v1(5);
    int x;
    cout << "Enter 5 integers (seperated by spaces):" << endl;
    for (int i=0; i<5; i++)
      cin >> v1[i];
    cout << "You entered:" << endl;
    for (int i=0; i<5; i++)
      cout << v1[i] << ' ';
    cout << endl;
  }
  ______________________________________________________________________



  21.4.4.  Inserting and Erasing Vector Elements

  Along with operator[] as described above there are a number of other
  ways to change or access the elements in a vector.


  ·  push_back will add a new element to the end of a vector.

  ·  pop_back will remove the last element of a vector.

  ·  insert will insert one or more new elements, at a designated
     position, in the vector.

  ·  erase will remove one or more elements from a vector between
     designated positions.

  Note that insert and erase are expensive operations on vectors. If you
  use them a lot then you should consider using the list data structure
  for which they are more efficient.


  ______________________________________________________________________
  <vector-mod.cc>=
  #include <iostream.h>
  #include <vector.h>

  void main()
  {
    vector<int> v;

    for (int i=0; i<10; i++) v.push_back(i);
    cout << "Vector initialised to:" << endl;
    for (int i=0; i<10; i++) cout << v[i] << ' ' ;
    cout << endl;

    for (int i=0; i<3; i++) v.pop_back();
    cout << "Vector length now: " << v.size() << endl;
    cout << "It contains:" << endl;
    for (int i=0; i<v.size(); i++) cout << v[i] << ' ';
    cout << endl;

    int a1[5];
    for (int i=0; i<5; i++) a1[i] = 100;

    v.insert(& v[3], & a1[0],& a1[3]);
    cout << "Vector now contains:" << endl;
    for (int i=0; i<v.size(); i++) cout << v[i] << ' ';
    cout << endl;

    v.erase(& v[4],& v[7]);
    cout << "Vector now contains:" << endl;
    for (int i=0; i<v.size(); i++) cout << v[i] << ' ';
    cout << endl;
  }
  ______________________________________________________________________



  In the above a vector v has been declared then initialised using
  push_back. Then some elements have been trimmed off it's end using
  pop_back. Next an ordinary integer array has been created and then
  some of its elements inserted into v using insert. Finally erase has
  been used to remove elements from v. The functions used above take
  arguments as follows.


  ·  push_back takes a single argument of the type of the elements held
     in the vector.

  ·  pop_back takes no arguments. It is a mistake to use pop_back on an
     empty vector.

  ·  insert has three forms:

  ·  insert(pos, T& x) which will insert the single element x at
     position pos in the vector.

  ·  insert(pos, start, end) which inserts a sequence of elements from
     some other container at position pos in the vector. The

  ·  sequence of elements is identified as starting at the start element
     and continuing to, but not including, the end element.

  ·  insert(pos, int rep, T& x) inserts rep copies of x at position pos
     in the vector.

     As indicated in the code above the position pos should be the
     address of the element to insert at, whilst the start and end
     arguments are likewise also addresses. (The true story is that they
     are iterators -- see next subsection and following section).

  ·  erase has two forms (pos, start and end have the same types as for
     the insert function):

  ·  erase(pos) which will remove the element at position pos in the
     vector.

  ·  insert(start,end) which will remove elements starting at postion
     start upto, but not including, the element at position end.

  21.4.5.  Vector Iterators


  The simple way to step through the elements of a vector v is as we
  have done above:


  ______________________________________________________________________
  for (int i=0; i<v.size(); i++) { ... v[i] ... }
  ______________________________________________________________________



  Another way is to use iterators. An iterator can be thought of as a
  pointer into the container, incrementing the iterator allows you to
  step through the container. For container types other than vectors
  iterators are the only way to step through the container.

  For a vector containing elements of type T:


  ______________________________________________________________________
  vector<T> v;
  ______________________________________________________________________



  an iterator is declared as follows:


  ______________________________________________________________________
  vector<T>::iterator i;
  ______________________________________________________________________



  Such iterators are constructed and returned by the functions begin()
  and end(). You can compare two iterators (of the same type) using ==
  and !=, increment using ++ and dereference using *. [In fact vector
  iterators allow more operations on them - see next section for more
  information].

  Here is an illustration of how to use iterators with vectors.



  ______________________________________________________________________
  <vector-iterator.cc>=
  #include <iostream.h>
  #include <vector.h>

  void main()
  {
    vector<int> v(10);
   first is ``less'' than the second

    int j = 1;

    vector<int>::iterator i;

    // Fill the vector v with integers 1 to 10.
    i = v.begin();
    while (i != v.end())
    {
      *i = j;
      j++;
      i++;
    }

    // Square each element of v.
    for (i=v.begin(); i!=v.end(); i++) *i = (*i) * (*i);

    // Print out the vector v.
    cout << "The vector v contains: ";
    for (i=v.begin(); i!=v.end(); i++) cout << *i << ' ';
    cout << endl;

  }
  ______________________________________________________________________



  Note how *i can be used on the left-hand side of an assignment
  statement so as to update the element pointed at by i, and on the
  right-hand side to access the current value.

  21.4.6.  Comparing Vectors

  You can compare two vectors using == and <. == will return true only
  if both vectors have the same number of elements and all elements are
  equal. The < functions performs a lexicographic comparison of the two
  vectors. This works by comparing the vectors element by element.
  Suppose we are comparing v1 and v2 (that is v1 < v2?). Set i=0. If
  v1[i] < v2[i] then return true, if v1[i] > v2[i] then return false,
  otherwise increment i (that is move on to the next element). If the
  end of v1 is reached before v2 return true, otherwise return false.
  Lexicographic order is also known as dictionary order. Some examples:


  ______________________________________________________________________
  (1,2,3,4) < (5,6,7,8,9,10) is false.
  (1,2,3) < (1,2,3,4) is true
  (1,2,3,4) < (1,2,3) is false
  (0,1,2,3) < (1,2,3) is true
  ______________________________________________________________________



  The following code illustrates the third example above.



  ______________________________________________________________________
  <vector-comp.cc>=
  #include <vector.h>
  #include <iostream.h>

  void main()
  {
    vector<int> v1;
    vector<int> v2;
    for (int i=0; i<4; i++) v1.push_back(i+1);
    for (int i=0; i<3; i++) v2.push_back(i+1);

    cout << "v1: ";
    for (int i=0; i<v1.size(); i++) cout << v1[i] << ' ';
    cout << endl;

    cout << "v2: ";
    for (int i=0; i<v2.size(); i++) cout << v2[i] << ' ';
    cout << endl;

    cout << "v1 < v2 is: " << (v1<v2 ? "true" : "false") << endl;
  }
  ______________________________________________________________________


  The comparison operators <= and >= also work.

  21.5.  Iterators and the STL

  See the section ``STL References''

  21.6.  Lists

  See the section ``STL References''

  21.7.  Sets

  The set container type allows an user to store and retrieve elements
  directly rather than through an index into the container. The set
  container acts as a mathematical set in that it holds only distinct
  elements. However unlike a mathematical set, elements in a set
  container are held in (an user-supplied) order. In practise this is
  only a minor restriction on treating a set container as an
  implementation of the mathematical set abstract data type, and it
  allows for a much more efficent implementation than an unordered
  approach.

  21.7.1.  Constructing Sets

  Two template arguments are required to construct a set container --
  the type of the objects the set is to contain and a function object
  that can compare two elements of the given type, that is:


  ______________________________________________________________________
  set<T, Compare> s;
  ______________________________________________________________________



  (The declaration set < T > s should also be possible -- it would use a
  default template argument less < T > as the second argument, but many
  C++ compilers (including g++) cannot as yet cope with default template
  arguments.)


  For simple types T we can use the function object less < T >  (
  without having to worry about what a ``function object'' is), for
  example all the following are legal set declarations.


  ______________________________________________________________________
  set<int, less<int> > s1;
  set<double, less<double> > s2;
  set<char, less<char> > s3;
  set<string, less<string> > s4;
  ______________________________________________________________________



  (Note that the space between the two final >'s in the template is
  required - otherwise the compiler will interpret >> as the right shift
  operator.) In each of these cases the function object makes use of the
  operator < as defined for the the underlying type (that is int,
  double, char and string).

  The following code declares a set of integers, then adds some integers
  to the set using the insert method and then prints out the set members
  by iterating through the set. You will note that the set's contents
  are printed out in ascending order even though they were added in no
  particular order.


  ______________________________________________________________________
  <set-construct1.cc>=
  #include <iostream.h>
  #include <set.h>

  void main()
  {
    set<int, less<int> > s;
    set<int, less<int> >::iterator i;

    s.insert(4);
    s.insert(0);
    s.insert(-9);
    s.insert(7);
    s.insert(-2);
    s.insert(4);
    s.insert(2);

    cout << The set contains the elements: ;
    for (i=s.begin(); i!=s.end(); i++) cout << *i << ' ';
    cout << endl;
  }
  ______________________________________________________________________



  Note that 4 is added twice but only turns up once on the list of
  elements -- which is what one expects of a set.

  21.7.2.  What are Function Objects?


  One of the nifty features of C++ is the ability to overload operators,
  so that one can have + mean whatever one likes for your newly designed
  class. One of the operators C++ allows you to overload is the function
  call operator () and this allows you to create classes whose instances
  can behave like functions in many ways. These are function objects.


  Here is a simple example.


  ______________________________________________________________________
  <function-object.cc>=
  #include <iostream.h>

  template<class T>
  class square {
  public:
    T operator()(T x) { return x*x; }
  };
  // This can be used with any T for which * is defined.

  void main()
  {
    // Create some function objects.
    square<double> f1;
    square<int> f2;

    // Use them.
    cout << 5.1^2 =  << f1(5.1) << endl;
    cout << 100^2 =  << f2(100) << endl;

    // The following would result in a compile time error.
    // cout << 100.1^2 =  << f2(100.1) << endl;

  }
  ______________________________________________________________________



  Function objects are used in a number of places in the STL. In
  particular they are used when declaring sets and maps.

  The function object required for these purposes, let's suppose it is
  called comp, must satisfy the following requirements.


  1. If comp(x,y) and comp(y,z) are true for objects x, y and z then
     comp(x,z) is also true.

  2. comp(x,x) is false for every object x.

  If for any particular objects x and y, both comp(x,y) and comp(y,x)
  are false then x and y are deemed to be equal.

  This, in fact, is just the behaviour of the strictly-less-than
  relation (ie < ) on numbers. The function object less < T > used above
  is defined in terms of a < operator for the type T. It's definition
  can be thought of as follows.


  ______________________________________________________________________
  template<class T>
  struct less {
    bool operator()(T x, T y) { return x<y; }
  }
  ______________________________________________________________________



  (The actual definition uses references, has appropriate const
  annotations and inherits from a template class binary_function.)


  This means that if the type T has operator < defined for it then you
  can use less < T > as the comparator when declaring sets of T. You
  might still want to use a special purpose comparator if the supplied <
  operator is not appropriate for your purposes. Here is another
  example. This defines a simple class with a definition of operator <
  and a function object that performs a different comparison. Note that
  the overloaded < and () operators should be given const annotations so
  that the functions work correctly with the STL.



  ______________________________________________________________________
  <set-construct2.cc>=
  #include <iostream.h>
  #include <set.h>

  // This class has two data members. The overloaded operator< compares
  // such classes on the basis of the member f1.
  class myClass {
  private:
    int f1;
    char f2;
  public:
    myClass(int a, char b) : f1(a), f2(b) {}
    int field1() const { return f1; }
    char field2() const { return f2; }
    bool operator<(myClass y) const
          { return (f1<y.field1()); }
  };

  // This function object compares objects of type myClass on the basis
  // of the data member f2.
  class comp_myClass {
  public:
    bool operator()(myClass c1, myClass c2) const
           { return (c1.field2() < c2.field2()); }
  };

  void main()
  {
    set<myClass, less<myClass> > s1;
    set<myClass, less<myClass> >::iterator i;
    set<myClass, comp_myClass> s2;
    set<myClass, comp_myClass>::iterator j;

    s1.insert(myClass(1,'a'));
    s2.insert(myClass(1,'a'));
    s1.insert(myClass(1,'b'));
    s2.insert(myClass(1,'b'));
    s1.insert(myClass(2,'a'));
    s2.insert(myClass(2,'a'));

    cout << Set s1 contains: ;
    for (i=s1.begin(); i!=s1.end(); i++)
      { cout << ( << (*i).field1() << ,
                    << (*i).field2() << ) << ' ';
      }
    cout << endl;

    cout << Set s2 contains: ;
    for (j=s2.begin(); j!=s2.end(); j++)
      { cout << ( << (*j).field1() << ,
                    << (*j).field2() << ) << ' ';
      }
    cout << endl;

  }
  ______________________________________________________________________



  The set s1 contains (1,a) and (2,a) as comparison is on the data
  member f1, so that (1,a) and (1,b) are deemed the same element. The
  set s2 contains (1,a) and (1,b) as comparison is on the data member
  f2, so that (1,a) and (2,a) are deemed the same element.


  21.7.3.  A Printing Utility

  The way we have printed out the sets in the previous examples is a
  little awkward so the following header file containing a simple
  overloaded version of operator<<  has been written.  It works fine for
  small sets with simple element types.


  ______________________________________________________________________
  <printset.h>=
  #ifndef _PRINTSET_H
  #define _PRINTSET_H

  #include <iostream.h>
  #include <set.h>

  template<class T, class Comp>
  ostream& operator<<(ostream& os, const set<T,Comp>& s)
  {
    set<T,Comp>::iterator iter = s.begin();
    int sz = s.size();
    int cnt = 0;

    os << {;
    while (cnt < sz-1)
      {
        os << *iter << ,;
        iter++;
        cnt++;
      }
    if (sz != 0) os << *iter;
    os << };

    return os;
  }
  #endif
  ______________________________________________________________________



  The use here of << as an output routine for a set assumes that << has
  been defined for the set elements, and uses this to print a comma
  delimited list of the set elements wrapped in curly braces. It will be
  used without comment in the following examples.

  21.7.4.  How Many Elements?


  You can determine if a set is empty or not by using the empty()
  method. You can find out how many elements there are in a set by using
  the size() method. These methods take no arguments, empty() returns
  true or false and size() returns an integer.



  ______________________________________________________________________
  <set-size.cc>=
  #include <iostream.h>
  #include <set.h>
  #include printset.h

  void main()
  {
    set<int, less<int> > s;

    cout << The set s is
         << (s.empty() ? empty. : non-empty.) << endl;
    cout << It has  << s.size() <<  elements. << endl;

    cout << Now adding some elements... << endl;

    s.insert(1);
    s.insert(6);
    s.insert(7);
    s.insert(-7);
    s.insert(5);
    s.insert(2);
    s.insert(1);
    s.insert(6);

    cout << The set s is now
         << (s.empty() ? empty. : non-empty.) << endl;
    cout << It has  << s.size() <<  elements. << endl;
    cout << s =  << s << endl;
  }
  ______________________________________________________________________



  21.7.5.  Checking the Equality of Sets.

  Two sets may be checked for equality by using ==. This equality test
  works by testing in order the corresponding elements of each set for
  equality using T::operator==.


  ______________________________________________________________________
  <set-equality.cc>=
  #include <iostream.h>
  #include <set.h>
  #include printset.h

  void main()
  {
    set<int, less<int> > s1, s2 ,s3;

    for (int i=0; i<10; i++)
    {
      s1.insert(i);
      s2.insert(2*i);
      s3.insert(i);
    }

    cout << s1 =  << s1 << endl;
    cout << s2 =  << s2 << endl;
    cout << s3 =  << s3 << endl;
    cout << s1==s2 is:  << (s1==s2 ? true. : false.) << endl;
    cout << s1==s3 is:  << (s1==s3 ? true. : false.) << endl;
  }
  ______________________________________________________________________

  It is also possible to compare two sets using <. The comparison s1 <
  s2 is true if the set s1 is lexicographically less than the set s2,
  otherwise it is false.

  21.7.6.  Adding and Deleting Elements

  The way to add elements to a set is to use the insert method (as we
  have done above). The way to delete elements from a set is to use the
  erase method.

  For a set holding elements of type T these methods come in following
  forms:

  ·  pair < iterator, bool> insert(T& x). This is the standard insert
     function. The return value may be ignored or used to test if the
     insertion succeeded (that is the element was not already in the
     set). If the insertion succeeded the boolean component will be true
     and the iterator will point at the just inserted element. If the
     element is already present the boolean component will be false and
     the iterator will point at the element x already present.


  ·  iterator insert(iterator position, T& x). This version of the
     insert function takes, in addition to the element to insert, an
     iterator stating where the insert function should begin to search.
     The returned iterator points at the newly inserted element, (or the
     already present element).


  ·  int erase(T& x). This version of the erase method takes an element
     to delete and returns 1 if the element was present (and removes it)
     or 0 if the element was not present.


  ·  void erase(iterator position). This version takes an iterator
     pointing at some element in the set and removes that element.


  ·  void erase(iterator first, iterator last). This verion takes two
     iterators pointing into the set and removes all the elements in the
     range [ first,last ] .

  The following example illustrates these various forms.



  ______________________________________________________________________
  <set-add-delete.cc>=
  #include <iostream.h>
  #include <set.h>
  #include printset.h

  void main()
  {
    set<int, less<int> > s1;

    // Insert elements in the standard fashion.
    s1.insert(1);
    s1.insert(2);
    s1.insert(-2);

    // Insert elements at particular positions.
    s1.insert(s1.end(), 3);
    s1.insert(s1.begin(), -3);
    s1.insert((s1.begin()++)++, 0);

    cout << s1 =  << s1 << endl;

    // Check to see if an insertion has been successful.
    pair<set<int, less<int> >::iterator,bool> x = s1.insert(4);
    cout << Insertion of 4  << (x.second ? worked. : failed.)
         <<  endl;
    x = s1.insert(0);
    cout << Insertion of 0  << (x.second ? worked. : failed.)
         <<  endl;

    // The iterator returned by insert can be used as the position
    // component of the second form of insert.
    cout << Inserting 10, 8 and 7. << endl;
    s1.insert(10);
    x=s1.insert(7);
    s1.insert(x.first, 8);

    cout << s1 =  << s1 << endl;

    // Attempt to remove some elements.
    cout << Removal of 0  << (s1.erase(0) ? worked. : failed.)
         << endl;
    cout << Removal of 5  << (s1.erase(5) ? worked. : failed.)
         << endl;

    // Locate an element, then remove it. (See below for find.)
    cout << Searching for 7. << endl;
    set<int,less<int> >::iterator e = s1.find(7);
    cout << Removing 7. << endl;
    s1.erase(e);

    cout << s1 =  << s1 << endl;

    // Finally erase everything from the set.
    cout << Removing all elements from s1. << endl;
    s1.erase(s1.begin(), s1.end());
    cout << s1 =  << s1 << endl;
    cout << s1 is now  << (s1.empty() ? empty. : non-empty.)
         << endl;
  }
  ______________________________________________________________________



  21.7.7.  Finding Elements


  We mention two member functions that can be used to test if an element
  is present in a set or not.


  ·  iterator find(T& x). This searches for the element x in the set. If
     x is found it returns an iterator pointing at x otherwise it
     returns end().

  ·  int count(T& x). This returns 1 if it finds x in the set and 0
     otherwise. (The count function for multisets returns the number of
     copies of the element in the set which may be more than 1. Hence, I
     guess, the name of the function.)

  The use of find has been illustrated above. We could use count to
  write a simple template based set membership function. (This should
  also provide a version that takes a reference to the argument x.)


  ______________________________________________________________________
  <setmember.h>=
  #ifndef _SETMEMBER_H
  #define _SETMEMBER_H
  #include <set.h>

  template<class T, class Comp>
  bool member(T x, set<T,Comp>& s)
  {
   return (s.count(x)==1 ? true : false);
  }
  #endif

  Which might be used as follows.

  <set-membership.cc>=
  #include <iostream.h>
  #include <set.h>
  #include printset.h
  #include setmember.h

  void main()
  {
    set<int, less<int> > s;
    for (int i= 0; i<10; i++) s.insert(i);
    cout << s =  << s << endl;
    cout << 1 is  << (member(1,s) ?  : not) <<  a member of s
         <<  endl;
    cout << 10 is  << (member(10,s) ?  : not) <<  a member of s
         <<  endl;
  }
  ______________________________________________________________________



  21.7.8.  Set Theoretic Operations


  The STL supplies as generic algorithms the set operations includes,
  union, intersection, difference and symmetric diffference. To gain
  access to these functions you need to include algo.h. (In what follows
  iter stands for an appropriate iterator).



  ·  bool includes(iter f1,iter l1,iter f2,iter l2).

     This checks to see if the set represented by the range [f2,l2] is
     included in the set [f1,l1]. It returns true if it is and false
     otherwise. So to check to see if one set is included in another you
     would use


     includes(s1.begin(), s1.end(), s2.begin(), s2.end())

     The includes function checks the truth of 3#3 ( that is of 4#4).
     This function assumes that the sets are ordered using the
     comparison operator <. If some other comparison operator has been
     used this needs to be passed to includes as an extra (function
     object) argument after the other arguments.


  ·  iter set_union(iter f1,iter l1,iter f2,iter l2,iter result).

     This forms the union of the sets represented by the ranges [f1,l1]
     and [f2,l2]. The argument result is an output iterator that points
     at the start of the set that is going to hold the union. The return
     value of the function is an output iterator that points at the end
     of the new set.

  The fact that the result argument is an output iterator means that you
  cannot use set_union in the following, natural, fashion:


  ______________________________________________________________________
        set<int, less<int> > s1, s2, s3;
        // Add some elements to s1 and s2 ...
        // Then form their union. (This does not work!)
        set_union(s1.begin(), s1.end(),
                  s2.begin(), s2.end(),
                  s3.begin());
  ______________________________________________________________________



  The reason is that begin() (also end()) when used with sets (or maps)
  returns a (constant) input iterator. This type of iterator allows you
  to access elements of the set for reading but not writing. (And this
  is a Good Thing since if you could assign to a dereferenced iterator
  (as in (*i)= ...) then you could destroy the underlying order of the
  set.)

  The solution is to use an insert iterator based on the set type. This,
  basically, converts an assignment (*i)=value (which is illegal) into a
  (legal) insertion s.insert(i,value) (where s is the set object that
  the iterator i is pointing into). It is used as follows:


  ______________________________________________________________________
        // Typedef for convenience.
        typedef set<int, less<int> > intSet;
        intSet s1, s2, s3;
        // Add some elements to s1 and s2 ...
        // Then form their union.
        set_union(s1.begin(), s1.end(),
                  s2.begin(), s2.end(),
                  insert_iterator<intSet>(s3,s3.begin()) );
  ______________________________________________________________________



  Here is an example illustrating all these operations.



  ______________________________________________________________________
  <set-theory.cc>=
  #include <iostream.h>
  #include <set.h>
  #include <algo.h>
  #include <iterator.h>
  #include printset.h

  void main()
  {
    typedef set<int, less<int> > intSet;

    intSet s1, s2, s3, s4;

    for (int i=0; i<10; i++)
    { s1.insert(i);
      s2.insert(i+4);
    }
    for (int i=0; i<5; i++) s3.insert(i);

    cout << s1 =  << s1 << endl;
    cout << s2 =  << s2 << endl;
    cout << s3 =  << s3 << endl;

    // Is s1 a subset of s2?
    bool test = includes(s2.begin(),s2.end(),s1.begin(),s1.end());
    cout << s1 subset of s2 is  << (test ? true. : false.) << endl;

    // Is s3 a subset of s1?
    test = includes(s1.begin(),s1.end(),s3.begin(),s3.end());
    cout << s3 subset of s1 is  << (test ? true. : false.) << endl;

    // Form the union of s1 and s2.
    set_union(s1.begin(), s1.end(), s2.begin(), s2.end(),
                     insert_iterator<intSet>(s4,s4.begin()) );
    cout << s1 union s2 =  << s4 << endl;

    // Erase s4 and form intersection of s1 and s2. (If we don't erase
    // s4 then we will get the previous contents of s4 as well).
    s4.erase(s4.begin(),s4.end());
    set_intersection(s1.begin(), s1.end(), s2.begin(), s2.end(),
                     insert_iterator<intSet>(s4,s4.begin()) );
    cout << s1 intersection s2 =  << s4 << endl;

    // Now set difference.
    s4.erase(s4.begin(),s4.end());
    set_difference(s1.begin(), s1.end(), s2.begin(), s2.end(),
                     insert_iterator<intSet>(s4,s4.begin()) );
    cout << s1 minus s2 =  << s4 << endl;

    // Set difference is not symmetric.
    s4.erase(s4.begin(),s4.end());
    set_difference(s2.begin(), s2.end(), s1.begin(), s1.end(),
                     insert_iterator<intSet>(s4,s4.begin()) );
    cout << s2 minus s1 =  << s4 << endl;

    // Finally symmetric difference.
    s4.erase(s4.begin(),s4.end());
    set_symmetric_difference(s1.begin(), s1.end(), s2.begin(), s2.end(),
                     insert_iterator<intSet>(s4,s4.begin()) );
    cout << s1 symmetric_difference  s2 =  << s4 << endl;

    // Which is symmetric!
    s4.erase(s4.begin(),s4.end());
    set_symmetric_difference(s2.begin(), s2.end(), s1.begin(), s1.end(),
                     insert_iterator<intSet>(s4,s4.begin()) );
    cout << s2 symmetric_difference  s1 =  << s4 << endl;
  }
  ______________________________________________________________________



  21.8.  Maps

  See the section ``STL References''

  21.9.  STL Algorithms

  See the section ``STL References''

  22.  Threads in C++


  ·  IBM pthread User Guide, Thread concepts, API reference
     <http://www.as400.ibm.com/developer/threads/uguide/document.htm>
     and mirror site is at IBM main site
     <http://java.icmc.sc.usp.br/library/books/ibm_pthreads/document.htm>


  ·  QpThread Library for C++ provides object oriented framework in C++
     for threads and Unix signals on top of system level threads
     (currently POSIX Threads) <http://lin.fsid.cvut.cz/~kra/index.html>


  ·  ThreadJack supports Java-like multi-thread programming model with
     platform independent C++ class library
     <http://www.esm.co.jp/divisions/open-sys/ThreadJack/index-e.html>
     and here is the download-site <http://www.esm.co.jp/divisions/open-
     sys/ThreadJack/source-dl-e.html>


  ·  APE is the "APE Portable Environment" and class libraries for
     writing portable threaded servers in C++, under UNIX (pthread) and
     Win32 API's.  APE provides portable class abstraction for threads,
     sockets, file handling, and synchronization objects. The goal of
     APE is to make writing threaded servers in C++ both practical and
     convient, even for small and simple projects, and hence simplicity
     and low runtime overhead are design goals
     <http://www.voxilla.org/projects/projape.html>


  ·  Portabale Thread Lib  <http://www.media.osaka-cu.ac.jp/~k-abe/PTL>


  ·  Thread-Recyling in C++  <http://www.sigs.de/html/kuhlmann.html>

  22.1.  Threads Tutorial


  ·  You can download all the tutorials in one file from aldev-site
     <http://www.aldev.8m.com/cppsrc.html>


  ·  Threads tutorial is at
     <http://www.math.arizona.edu/swig/pthreads/threads.html>


  ·  HERT tutorial at  <http://www.hert.org/docs/tutorials>, go here to
     search for "Threads".



  ·  Intro to threads at linuxjournal <http://www2.linuxjournal.com/lj-
     issues/issue61/3138.html>


  ·  North Arizona Univ NAU
     <http://www.cse.nau.edu/~mc8/Thread/Contents.html>


  ·  Posix threads Acctcom multi-thread
     <http://users.actcom.co.il/~choo/lupg/tutorials/multi-thread/multi-
     thread.html>

  22.2.  Designing a Thread Class in C++

  This section is written by Ryan Teixeira and the document is located
  here
  <http://www.geocities.com/SiliconValley/Heights/6038/dthreads.html> .

  22.2.1.  Introduction

  Multi threaded programming is becomming ever more popular. This
  section presents a design for a C++ class that will encapsulate the
  threading mechanism. Certain aspects of thread programming, like
  mutexes and semaphores are not discussed here. Also, operating system
  calls to manipulate threads are shown in a generic form.

  22.2.2.  Brief Introduction To Threads

  To understand threads one must think of several programs running at
  once. Imagine further that all these programs have access to the same
  set of global variables and function calls.  Each of these programs
  would represent a thread of execution and is thus called a thread.
  The important differentiation is that each thread does not have to
  wait for any other thread to proceed. All the threads proceed
  simultaneously. To use a metaphor, they are like runners in a race, no
  runner waits for another runner. They all proceed at their own rate.

  Why use threads you might ask. Well threads can often improve the
  performance of an application and they do not incur significant
  overhead to implement. They effectively give good bang for a buck.
  Imagine an image server program that must service requests for images.
  The program gets a request for an image from another program. It must
  then retieve the image from a database and send it to the program that
  requested it. If the server were implemented in a single threaded
  approach, only one program could request at a time. When it was busy
  retrieving an image and sending it to a requestor, it could not
  service other requests. Of course one could still implement such a
  system without using threads. It would be a challenge though. Using
  threads, one can very naturally design a system to handle multiple
  requests. A simple approach would be to create a thread for each
  request received. The main thread would create this thread upon
  receipt of a request. The thread would then be responsible for the
  conversation with the client program from that point on. After
  retrieving the image, the thread would terminate itself. This would
  provide a smooth system that would continue to service requests even
  though it was busy serviceing other requests at the same time.

  22.2.3.  Basic Approach

  The create a thread, you must specify a function that will become the
  entry point for the thread. At the operating system level, this is a
  normal function. We have to do a few tricks to wrap a C++ class around
  it because the entry function cannot be a normal member function of a
  class. However, it can be a static member function of a class. This is
  what we will use as the entry point. There is a gotcha here though.
  Static member functions do not have access to the this pointer of a
  C++ object. They can only access static data. Fortunately, there is
  way to do it. Thread entry point functions take a void * as a
  parameter so that the caller can typecast any data and pass in to the
  thread. We will use this to pass this to the static function. The
  static function will then typecast the void * and use it to call a non
  static member function.

  22.2.4.  The Implementation

  It should be mentioned that we are going to discuss a thread class
  with limited functionality. It is possible to do more with threads
  than this class will allow.


  ______________________________________________________________________
  class Thread
  {
     public:
        Thread();
        int Start(void * arg);
     protected:
        int Run(void * arg);
        static void * EntryPoint(void*);
        virtual void Setup();
        virtual void Execute(void*);
        void * Arg() const {return Arg_;}
        void Arg(void* a){Arg_ = a;}
     private:
        THREADID ThreadId_;
        void * Arg_;

  };

  Thread::Thread() {}

  int Thread::Start(void * arg)
  {
     Arg(arg); // store user data
     int code = thread_create(Thread::EntryPoint, this, & ThreadId_);
     return code;
  }

  int Thread::Run(void * arg)
  {
     Setup();
     Execute( arg );
  }

  /*static */
  void * Thread::EntryPoint(void * pthis)
  {
     Thread * pt = (Thread*)pthis;
     pthis->Run( Arg() );
  }

  virtual void Thread::Setup()
  {
          // Do any setup here
  }

  virtual void Thread::Execute(void* arg)
  {
          // Your code goes here
  }
  ______________________________________________________________________

  It is important to understand that we are wrapping a C++ object around
  a thread. Each object will provide an interface to a single thread.
  The thread and the object are not the same.  The object can exist
  without a thread. In this implementation, the thread does not actually
  exist until the Start function is called.

  Notice that we store the user argument in the class.  This is
  necessary because we need a place to store it temporarily until the
  thread is started. The operating system thread call allows us to pass
  an argument but we have used it to pass the this pointer. So we store
  the real user argument in the class itself and when the execute
  function is called it can get access to the argument.

  Thread(); This is the constructor.

  int Start(void * arg); This function provides the means to create the
  thread and start it going. The argument arg provides a way for user
  data to be passed into the thread. Start() creates the thread by
  calling the operating system thread creation function.

  int Run(void * arg); This is a protected function that should never be
  tampered with.

  static void * EntryPoint(void * pthis); This function serves as the
  entry point to the thread.  It simply casts pthis to Thread * and

  virtual void Setup(); This function is called after the thread has
  been created but before Execute() is called. If you override this
  function, remember to call the parent class Execute().

  virtual void Execute(void *); You must override this function to
  provide your own functionality.

  22.2.5.  Using The Thread Class

  To use the thread class, you derive a new class. you override the
  Execute() function where you provide your own functionality. You may
  override the Setup() function to do any start up duties before Execute
  is called. If you override Setup(), remember to call the parent class
  Setup().

  22.2.6.  Conclusion

  This section presented an implementation of a thread class written in
  C++.  Of course it is a simple approach but it provides a sound
  foundation upon which to build a more robust design.

  If you have comments or suggestions, email to Ryan Teixeira

  23.  C++ Utilities

  Visit the following sites for C++ Utilities

  ·  C++ Binary File I/O
     <http://www.angelfire.com/nv/aldev/cpphowto/cpp_BinaryFileIO.html>
     and at mirror site
     <http://aldev.50megs.com/cpphowto/cpp_BinaryFileIO.html>


  ·  Portability Guide
     <http://www.angelfire.com/nv/aldev/cpphowto/cpp_PortabilityGuide.html>
     and at mirror site
     <http://aldev.50megs.com/cpphowto/cpp_PortabilityGuide.html>



  ·  Snippets collections of C++ routines
     <http://www.angelfire.com/nv/aldev/cpphowto/cpp_Snippets.html> and
     at mirror site <http://aldev.50megs.com/cpphowto/cpp_Snippets.html>
     and at snippets site
     <http://www.strangecreations.com/library/snippets>


  ·  escape ISB for C++ - Provides information on how to develop and
     program distributed, object-based applications in C++ for Windows
     and Unix using the Netscape Internet Service Broker
     <http://docs.iplanet.com/docs/manuals/enterprise/cpluspg/contents.htm>


  ·  Common c++  <http://www.voxilla.org/projects/projape.html>


  ·  Large List of free C++ libs
     <http://www.thefreecountry.com/developercity/freelib.html>


  ·  C++ Tools  <http://development.freeservers.com>


  ·  C++ Tools CUJ  <http://www.cuj.com/code>


  ·  C++libs Univ of vaasa  <http://garbo.uwasa.fi/pc/c-lang.html>

  24.  Other Formats of this Document

  This document is published in 12 different formats namely - DVI,
  Postscript, Latex, Adobe Acrobat PDF, LyX, GNU-info, HTML, RTF(Rich
  Text Format), Plain-text, Unix man pages, single HTML file and SGML.

  ·  You can get this HOWTO document as a single file tar ball in HTML,
     DVI, Postscript or SGML formats from -
     <ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/other-formats/> and
     <http://www.linuxdoc.org/docs.html#howto>

  ·  Plain text format is in:
     <ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO> and
     <http://www.linuxdoc.org/docs.html#howto>

  ·  Single HTML file format is in:
     <http://www.linuxdoc.org/docs.html#howto>

  ·  Translations to other languages like French, German, Spanish,
     Chinese, Japanese are in
     <ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO> and
     <http://www.linuxdoc.org/docs.html#howto> Any help from you to
     translate to other languages is welcome.

     The document is written using a tool called "SGML-Tools" which can
     be got from - <http://www.sgmltools.org> Compiling the source you
     will get the following commands like

  ·  sgml2html C++Programming-HOWTO.sgml     (to generate html file)

  ·  sgml2rtf  C++Programming-HOWTO.sgml     (to generate RTF file)

  ·  sgml2latex C++Programming-HOWTO.sgml    (to generate latex file)

  LaTeX documents may be converted into PDF files simply by producing a
  Postscript output using sgml2latex ( and dvips) and running the output
  through the Acrobat distill ( <http://www.adobe.com>) command as
  follows:
  ______________________________________________________________________
  bash$ man sgml2latex
  bash$ sgml2latex filename.sgml
  bash$ man dvips
  bash$ dvips -o filename.ps filename.dvi
  bash$ distill filename.ps
  bash$ man ghostscript
  bash$ man ps2pdf
  bash$ ps2pdf input.ps output.pdf
  bash$ acroread output.pdf &
  ______________________________________________________________________


  Or you can use Ghostscript command ps2pdf.  ps2pdf is a work-alike for
  nearly all the functionality of Adobe's Acrobat Distiller product: it
  converts PostScript files to Portable Document Format (PDF) files.
  ps2pdf is implemented as a very small command script (batch file) that
  invokes Ghostscript, selecting a special "output device" called
  pdfwrite. In order to use ps2pdf, the pdfwrite device must be included
  in the makefile when Ghostscript was compiled; see the documentation
  on building Ghostscript for details.

  This howto document is located at -

  ·  <http://sunsite.unc.edu/LDP/HOWTO/C++Programming-HOWTO.html>

  Also you can find this document at the following mirrors sites -

  ·  <http://www.caldera.com/LDP/HOWTO/C++Programming-HOWTO.html>

  ·  <http://www.WGS.com/LDP/HOWTO/C++Programming-HOWTO.html>

  ·  <http://www.cc.gatech.edu/linux/LDP/HOWTO/C++Programming-
     HOWTO.html>

  ·  <http://www.redhat.com/linux-info/ldp/HOWTO/C++Programming-
     HOWTO.html>

  ·  Other mirror sites near you (network-address-wise) can be found at
     <http://sunsite.unc.edu/LDP/hmirrors.html> select a site and go to
     directory /LDP/HOWTO/C++Programming-HOWTO.html


  In order to view the document in dvi format, use the xdvi program. The
  xdvi program is located in tetex-xdvi*.rpm package in Redhat Linux
  which can be located through ControlPanel | Applications | Publishing
  | TeX menu buttons.  To read dvi document give the command -


               xdvi -geometry 80x90 howto.dvi
               man xdvi



  And resize the window with mouse.  To navigate use Arrow keys, Page
  Up, Page Down keys, also you can use 'f', 'd', 'u', 'c', 'l', 'r',
  'p', 'n' letter keys to move up, down, center, next page, previous
  page etc.  To turn off expert menu press 'x'.

  You can read postscript file using the program 'gv' (ghostview) or The
  ghostscript program is in ghostscript*.rpm package and gv program is
  in gv*.rpm package in Redhat Linux which can be located through
  ControlPanel | Applications | Graphics menu buttons. The gv program is
  much more user friendly than ghostscript.  Also ghostscript and gv are
  available on other platforms like OS/2, Windows 95 and NT, you view
  this document even on those platforms.


  ·  Get ghostscript for Windows 95, OS/2, and for all OSes from
     <http://www.cs.wisc.edu/~ghost>

  To read postscript document give the command -


                       gv howto.ps
                       ghostscript howto.ps



  You can read HTML format document using Netscape Navigator, Microsoft
  Internet explorer, Redhat Baron Web browser or any of the 10 other web
  browsers.

  You can read the latex, LyX output using LyX a X-Windows front end to
  latex.

  25.  Copyright

  Copyright policy is GNU/GPL as per LDP (Linux Documentation project).
  LDP is a GNU/GPL project.  Additional requests are that you retain the
  author's name, email address and this copyright notice on all the
  copies. If you make any changes or additions to this document then you
  please intimate all the authors of this document.  Brand names
  mentioned in this document are property of their respective owners.

  26.  Appendix A String Program Files


  You can download all programs as a single tar.gz file from ``'' and
  give the following command to unpack

  ______________________________________________________________________
  bash$ man tar
  bash$ tar ztvf C++Programming-HOWTO.tar.gz
  This will list the table of contents

  bash$ tar zxvf C++Programming-HOWTO.tar.gz
  This will extract the files
  ______________________________________________________________________



  ·  Read the header file first and then see the example cpp program

  ·  String.h <http://www.angelfire.com/nv/aldev/cpphowto/String.h>

  ·  string_multi.h
     <http://www.angelfire.com/nv/aldev/cpphowto/string_multi.h>

  ·  example_String.cpp
     <http://www.angelfire.com/nv/aldev/cpphowto/example_String.cpp>



  ·  File manipulation class, only length() function is implemented..

  ·  File.h <http://www.angelfire.com/nv/aldev/cpphowto/File.h>

  ·  File.cpp <http://www.angelfire.com/nv/aldev/cpphowto/File.cpp>



  ·  The zap() implemented here ..

  ·  my_malloc.h
     <http://www.angelfire.com/nv/aldev/cpphowto/my_malloc.h>

  ·  my_malloc.cpp
     <http://www.angelfire.com/nv/aldev/cpphowto/my_malloc.cpp>



  ·  Implementation of string class...

  ·  String.cpp <http://www.angelfire.com/nv/aldev/cpphowto/String.cpp>

  ·  StringTokenizer.cpp
     <http://www.angelfire.com/nv/aldev/cpphowto/StringTokenizer.cpp>



  ·  Debug facilities ..

  ·  debug.h <http://www.angelfire.com/nv/aldev/cpphowto/debug.h>

  ·  debug.cpp <http://www.angelfire.com/nv/aldev/cpphowto/debug.cpp>

  ·  Makefile <http://www.angelfire.com/nv/aldev/cpphowto/Makefile>



  ·  Sample java file for testing the functionalities of String class ..

  ·  string.java
     <http://www.angelfire.com/nv/aldev/cpphowto/string.java>



