Macros in C

The #define directive is specially used to define a micro i.e. single identifier that are equivalent to expression , complete statement or group of statements.
      It is a fragment of code which has been given a name . Whenever the name is used , it is replaced by the contents of the macro.

Syntax:-

     #define macroname microexpansion


Example:- 

#define PI  3.14

#define ADD(a,b) (a+b)


Predefined Macros in C Language

Predefined                   Value  
  Macro

__DATE__                  String containing the
                                       current date

__FILE__                   String containing the file name

__LINE__                   Integer representing the
                                      current line number

__STDC__                 If follows ANSI standard
                                        C,then value is a
                                        non zero integer

__TIME__                  String containing the
                                        current time


How to use predefined Macros?

 Find the current time using C program

 #include <stdio.h>
 main()
 {
  printf("Current time : %s ", __TIME__);
 }


Output:-
   Current Time:- 12:32:43


Some Important C program using Macro:-

> C program to calculate the arae of circle using macro.

> C program to find the sum of two number using macro.

> C program to find square of a number using macro.

> C program to find maximum between two number using macro.




Some other important c program:-

Important C program of 1D Array

Important C program of Matrix(2D Array)

Important C program of string

Important C program using Function

Important C program using Recursive function

Click Here to download complete notes of C programming.