In C++, a variable is a name representing a memory location used to store and change data. Variables are declared with a specific type, such as int, float, or char, following rules that limit their naming conventions. For example, variable names can include letters, digits, and underscores but must start with a letter or underscore and cannot be reserved keywords.

1. C++ VARIABLE
A Variable is the name of memory location. It is used to store data. Its
value can be changed and it can be reused many times .
It is the way to represent memory location through symbol so that it can be easily identified.
C++ VARIABLE
Type variable_list ;
The example of declaring variable is given below :
Int x ;
Float y ;
Char z ;
Here x,y,z are the variables and int , float and char are data types .
5
MEMORY
Example :-
Int a=5;
a

2. RULES FOR DEFINIING VARIABLES
• A variable can have alphabets , digits and underscore.
• A variable name can start with the alphabet and underscore only. It
can not start with digit.
• No whitespace is allowed within variable name.
• A variable name must not be any reserved word or keyword example
char , float etc.
RULES FOR DEFINING VARIABLES
Example
Int _a=12;
Invalid variable
Int 12