Constants, Variables, and Data Types

Constants

Fixed values that do not  change during the execution of a program. Java supports several  types of  constants.

Integer  -           An integer constant refers to a sequence of digits. There are three

types of integers.

·        Decimal integer Ex:       137

·        Octal integer                 Ex:       037

·        Hexadecimal integer      Ex:       ox2

Real                             Ex:       0.0083

Character                     Ex:       ‘X’

Variables

A variable is an identifier that denotes a storage  location used to store a data value Unlike  constants that  remain  unchanged  during the execution  of a program. A variable may take different values at different  times  during  the execution  of the program.

Some variables names are:

            Mean

            Medium

            Height

Data Types

Every variable  in Java has a data type. Data types in java  under various   categories

• Integer Type
• Floating Point Type
• Character Type
• Boolean Type