Calculating Ratio In C language

#include <stdio.h>

void main()
{
    int p, q, r, s;
    float ratio;

    printf("\n Enter four integers ( seperates by space): ");
    scanf("%d %d %d %d", &p, &q, &r, &s);

    if ( (r-s) == 0 )
        {
        printf("\n Ratio is infinity, because (r-s) is 0.");
        exit(0);
        }

    else
        {
        ratio = (float)(p+q) / (float) (r-s);
        printf("\n Ratio is %.2f", ratio);
        }

   return 0;
}