Symbolic Constants

 Symbolic Constants:-

A symbolic constant is name that substitute for a sequence of character that cannot be changed i.e. constant. Constants in C++ refer to fixed values. Constant values do not change during the execution of a program. These fixed values are also called literals.  Constants can be of any of the basic data types like an integer constant, a floating constant, a character constant, or a string literal. A constant is used to describe a numerical value, or a character string. Numerical constants may be expressed as real constants, integer constants or character constants. The constants are treated just like regular variables except that their values cannot be modified after their definition. You must initialize a constant when it is created.

Defining Symbolic Constants:

There are two simple ways in C++ to define constants:

1.   Using #define pre-processor: The pre-processor directive #define can create a constant by specifying its name and value, separated by spaces.

2.      Using const keyword: The keyword const can create constant by specifying name of constant and assign its value to it using assignment operator.  

Syntax:

#define constant_name value;

const datatype constant = value;

Example:

#define pi 3.14;

const float pi = 3.14;

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