PI_By_Coprime

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define n 10000 // Number of iterations (pairs)

int gcd(int a, int b){
    if (a == 0 || b == 0){
       return 0;
    }
    if (a == b){
        return a;
    }
    if (a > b){
        return gcd(a-b, b);
    }
    return gcd(a, b-a);
}

int main()
{
    int i, a, b, c;
    double coprime, pi;
    time_t t;

    srand((unsigned) time(&t));
    coprime=0;

    for (i=0; i<n; i++){
        a = rand(); b=rand(); c=gcd(a, b);
        if (c==1){
            coprime++;
        }
    }
    pi=sqrt(6/(coprime/n));
    printf("\n\nPI=%f\n", pi);
}