Java program variables

3.1 Variables

A variable provides us with named storage that our programs can manipulate. 

Each variable in Java has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable.

You must declare all variables before they can be used. 

The basic form of a variable declaration is shown here:

data_type variable = value;

Here data type is one of Java's datatypes and variable is the name of the variable. To declare more than one variable of the specified type, you can use a comma-separated list.

Following are valid examples of variable declaration and initialization in Java:

int a, b, c;

// Declares three ints, a, b, and c.

int a = 10, b = 10;

// Example of initialization

double pi = 3.14159;

// declares and assigns a value of PI.

char a = 'a';

// the char variable a iis initialized with value 'a'

Constant: During the execution of program, value of variable may change. A constant represents permanent data that never changes. 

If you want use some value likes p=3.14159; no need to type every time instead you can simply define constant for p, following is the syntax for declaring constant.

Static final datatype ConstantName = value;

Example: stat

ic final float PI=3.14159;