Question

Write a C program to find the area of circle using preprocessor directives.

Answer 1

#include <stdio.h>

#define AREA_OF_CIRCLE(r) ((r)*(r)*3.1415926)

int main()
{
    double r = 5.0;

    printf("Radius of circle is %f\n", r);
    printf("Area of circle is %f\n", AREA_OF_CIRCLE(r));

    return 0;
}