Define Directive

Dear Visitors,
          In earlier post we tell you about the include directive.....
Today we are going to share with you knowledge about define directive.

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• The 'define' directive:- 

The 'define' directive is another important preprocessor directive. It is used to define a constant known as constant macro. A constant macro is an identifier, which is assigned a particular constant value. The value of identifier remains constant during the execution of program. Its general syntax is:

#include identifier expression  

Where

• Identifier:-

                             Specifies the identifier (or macro name) to which the constant value is to be assigned.

• Expression:-

                            Specified the constant value that is to be assigned to the identifier. It may be a constant value, a string or an arithmetic expression.

          For Example:-

In the following statements, PI has been assigned value 3.141593 and 'city' is assigned value Islamabad.

#define PI 3.141593

   #define city Islamabad