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

int main()
{
    int i = 0, k = 0;
    int n = 100000000;
    float x, y;

    srand(time(0));

    for( i=0 ; i < n  ; i++ )
    {
        x = rand() / (float)RAND_MAX;
        y = rand() / (float)RAND_MAX;
        if ( x*x + y*y < 1 ) k++;
    }

    printf("n=%d, pi=%f\n", n, 4.0 * k / n);

    return 0;
}