C++ Variable

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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.

Let’s see the syntax to declare a variable:

type variable_list; 

The example of declaring variable is given below:

int x;    
float y;    
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:

int x=5,b=10;  //declaring 2 variable of integer type    
float f=30.8;    
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:

int a;    
int _ab;    
int a30; 

Invalid variable names:

    int 4;    
    int x y;    
    int double;