A variable is the name of a 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.
|Boolean types||True or false value, as assigned|
|Integral types||int, char, byte, short, long|
|Floating point types||float and double|
|Nullable types||Nullable data types|
type variable_list; //The example of declaring a variable is given below: int i, j; double d; float f; char ch //Example of veriable declartion int i=2,j=4; //declaring 2 variable of integer type float f=40.2; char ch='B';
Rules for defining variables
- A variable can have alphabets, digits, and underscore.
- A variable name can start with the alphabet and underscore only. It can't start with a digit.
- No white space is allowed within the variable name.
- A variable name must not be any reserved word or keyword e.g. char, float, etc.
//Valid variable names: int x; int _x; int k20; //Invalid variable names: int 4; int x y; int double;