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Introduction of C++

C++ is an object oriented programming language.

What is C++?

C++ is an object oriented programming language. C++ is first object oriented programming language.

C++ was developed by Bjarne Stroustrup at AT & T's Bell Labs, USA in 1979.

Features of C++.

  • C++ is a middle level language.
  • C++ supports principles of object oriented paradigm.
  • C++ joins three separate programming traditions.
  • C++ is first object oriented programming system.

What is OOPS?

OOPS is a programming approach which revolvs around the concept of "object".
Any entity in the system that can be defined as a set of properties and set of operations performed using entity's property set, is known as object.'

  • Encapsulation
  • Data hiding
  • Abstraction
  • Polymorphism
  • Inheritance


variables are the names of memory locations where we store data.
variable name is any combination of alphabet (a to z or A to Z), digit(0 to 9) and underscore (_).

Rules for naming variables in C++

  • First character must be alphabet or underscore(_).
  • no commas, blanks allowed
  • no special symbol other than (_) allowed
  • variables names are case sensitive we must create meaningful variables name in our programms.

Types of variables

  • local
  • global
  • static

local variable

local variable can declare and defineinside function of constructor block. It cannot access outside of function block.

global variable

global variable can declare out side of function block. global variable can acces any where in program, if it is public.

static variable

static variable can declare at the class level. No need to create an object to access static variable.


Keywords are reserved words, whose meaning is already known to the compiler.

auto double struct int asm private
break else long switch catch public
case enum register typedef class protected
char extern return union delete template
const short float unsigned friend this
continue signed for void inline throw
default sizeof goto volatile new try
do static if while operator virtual

Difference between C and C++

  • c follows top down approach of programming
  • c++ follows bottom up approach of programming


comments are used to clarify something about the program in plain languagqe.

There are two types of comments in C++.

  • Single line comment.
  • Multi line comment.