C Macro

Abstract

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• Preprocessor replaces the Macro with the value before passing to the Compiler

#include <stdio.h>
#define PI 3.1415
 
int main()
{
    float radius, area;
    printf("Enter the radius: ");
    scanf("%f", &radius);
 
    // Notice, the use of PI
    area = PI*radius*radius;
 
    printf("Area=%.2f",area);
    return 0;
}

Function-like Macro

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Not same as Function, doesn’t have Type Safety

#include <stdio.h>
#define PI 3.1415
#define circleArea(r) (PI*r*r)
 
int main() {
    float radius, area;
 
    printf("Enter the radius: ");
    scanf("%f", &radius);
    area = circleArea(radius);
    printf("Area = %.2f", area);
 
    return 0;
}

Benefits

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• Saving memory of using variables to store the values