What are macros in C programming language?

Macro substitution is a mechanism that provides string replacement. It can be achieved by "##define".

It is used to replace the first part of the macro definition with the second part before the program is executed.

The first object can be a function type or an object.

Syntax

The syntax of the macro is as follows:

#define first_part second_part

Program

In the program, every time first_part appears, it will be replaced by second_part.

Online Demo

#include<stdio.h>
#define square(a) a*a
int main(){
int b,c;
printf("enter b element:");
scanf("%d",&b);
c=square(b);//replaces c=b*b before execution of program
printf("%d",c);
return 0;
}

Output

You will see the following output −

enter b element:4
16

Consider another program that interprets macro functions.

Live Demo

#include<stdio.h>
#define equation (a*b)+c
int main(){
   int a,b,c,d;
   printf("enter a,b,c elements:");
   scanf("%d %d %d",&a,&b,&c);
   d=equation;//replaces d=(a*b)+c before execution of program
   printf("%d",d);
   return 0;
}

Output

You will see the following output −

enter a,b,c elements: 4 7 9
37

The above is the detailed content of What are macros in C programming language?. For more information, please follow other related articles on the PHP Chinese website!