Variables in C++

A variable is a name of memory location. It is used to store data. Its value can be changed and it can be reused many times.

It is a way to represent memory location through symbol so that it can be easily identified.

Variable can also be thought as a container,which is storing some values

Let’s see the syntax to declare a variable:

                        type variable_list;   


The example of declaring variable is given below:

  1. int x;    
  2. float y;    
  3. char z;    


Here, x, y, z are variables and int, float, char are data types.

We can also provide values while declaring the variables as given below:

  1. int x=5,b=10;  //declaring 2 variable of integer type    
  2. float f=30.8;    
  3. char c=‘A’;    


Rules for defining variables

  • A variable can have alphabets, digits and underscore.
  • A variable name can start with alphabet and underscore only. It can’t start with digit.
  • No white space is allowed within variable name.
  • A variable name must not be any reserved word or keyword e.g. char, float etc.


  Valid variable names:

  1. int a;    
  2. int _ab;    
  3. int a30;    

Invalid variable names:

  1. int 4;    
  2. int x y;    
  3. int double;