pi

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

const int c = 10000000;

int main() {
    srand ( time(NULL) );

    float x,y,i=0.0;
    int s;
    for(s=0; s<c; s++) {
        x=1.*rand()/RAND_MAX;
        y=1.*rand()/RAND_MAX;
        i+=x*x+y*y<=1;
    }
    printf("%lf\n",4*i/c);

    return 0;
}