Java Variable

Variable:

Variable is an identifier whose value can be changed. or which store the data
Example:
int x=10;
x=20;

Variable declaration rules:

1.Variable name must be starts with alphabet or underscore or dollar symbol.
Example:
int age=10;
int _age=20;
int $age=30;

2.The max length of the Variable name is upto 32 characters.
3.If Variable name contains more than one word ,the second word onwards first letter should be
uppercase letter.
Example:
int studentAge=10;
int studentAgeDetails=10;
4.No spaces are allowed at the middle of the Variable declaration.
Example:
int student Age=10; (Invalid);
5.If Variable value contains constant value that Variable name must be
uppercase letter.
Example:
final float PI=3.14;
6.If constant Variable name contains more than one word ,it should be separated with underscore.
Example:
final float PI_VALUE=3.14;
7.All keywords are lower case letters.(52 Keywords in java)
Example:
int
float
char
8.We should not take keyword as a Variable name.
Example:
int if=10;(Invalid)
int If=10;(Valid)

Variable Defination types:

1.Initialization
2.Declaration
3.Assignment

Initialization:

It Means initialize the some value to the Variable.
Example:
int x=10;
Here 10 is initialize to the x.

Declaration:

In the declaration no value initialize to the Variable.
Example:
int x;

Assignment:

In the assignment assign the value to the Variable or assign Variable to the Variable.
Example:
int x;
x=10;(It is a value to Variable).

int y;
y=x;(It is a Variable to Variable).

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