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: static final float PI=3.14159;
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