Constant (programming)

A constant in a computer program is a value that can not be changed during the term of the program. The counterpart to this is a variable. Constants usually have semantic identifiers, which simplifies the handling and to prevent confusion with other constants. The term is however also used for literals ( literal constant ), which have no semantic identifiers. Therefore, it is clear to speak of symbolic constants with user-definable constants.

By defining constants code repetition can be avoided.

In the C language constants can be defined as a macro preprocessor.

Example

Example in the programming language BASIC: