CONSTANTS

A constant is a numeric type or non numeric type.It can be a number, character or a character 
string that can be used as a value  in a program.As the name implies, the value of a constant 
cannot be modified. A constant is immutable.Numeric data is primarily made up of numbers and 
can include decimal points.non numeric data may be composed of numbers,letters,blanks and any 
special characters supported by the system. In other words, non numeric data consists of 
alphanumeric characters,A non numeric data can be called as a literal.Constant are characterized 
by having a value and type.

Numeric constant of three types :

• integer constant,
• floating_point constant,
• character constant.