• C++ is an object-oriented programming language developed by Bjarne Stroustrup at AT & T Bell Laboratories in New Jersey, USA, in 1980.
  • It is developed from Simula67 and C programming language.
  • The new fundamental is class in C++ programming language other than C so it was given name ‘C with Classes’ for C++.
  • But in 1983 from the increment operator (++) of C language the new name was given C++.
  • In 1997 ANSI (American National Standard Institute) standardized C++.
  • C++ is super-set of C and it is similar to C language.
  • Most important facilities provided by C++ over C are: Class, Inheritance, function overloading and Operator overloading.
  • C language uses top-down structure of programming while C++ uses bottom-up structure.


  • C++ provides new type of comment. It is single line comment.
  • It starts with double slash (//) and end with the line.
  • C++ also provides the multi-line comment provided in C in which we write comment in between ‘/*’ and ‘*/’.
  • We can place multi-line comment in-between one statement while single line comment can’t.
  • It is generally used to give description in one line only.

‘iostream’ header file:

  • In C++ programs we have to include header file ‘iostream’ (Input Output STREAM file) as:

#include <iostream>

  • But some old version of C++ compiler uses iostream.h, iostream.hpp, iostream.hxx, etc. file as the header file.
  • This file mostly contains the classes and functions used for the input and output.

Input/Output Statement:

  • In C program we use ‘printf’ and ‘scanf’ to print and read value respectively.
  • These are the function while in C++ we use ‘cout’ and ‘cin’ class for printing and reading value respectively.
  • These both class are written in file ‘iostream.h’.
  • To print the output we use following statement:

      cout << “C++ is superset of C language”;

  • In above statement ‘cout’ is a class. ‘<<’ is an insertion or put to operator which is used to direct the output stream to ‘cout’. The output operation in C++ can be shown as under:

insertion operator

  • We are passing C++ variable and string stream to the ‘cout’ class object by the insertion operator and ‘cout’ will send the stream to output device (i.e. screen)
  • To read the value from the keyboard we use following statement:

       cin >>  a     // Here ‘a’ is integer variable

  • ‘cin’ is also class used for input. ‘>>’ is a get from or extraction operator which direct the input stream from ‘cin’ to the variable. The input operation can be shown as under:

extraction operator

  • cin’ class object reads the value from keyboard and direct the value to the variable by extraction operator.