【自殺】メンヘラMRの集い【うつ】

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

/* n : r = 1 : pi/4 */
double montecarlo(int n) {
int i, r;
double x, y;
for (i = 0, r = 0; i < n; i++) {
x = (double)rand()/(RAND_MAX+1.0);
y = (double)rand()/(RAND_MAX+1.0);
if ((x*x + y*y) < 1.0)
r++;
}
return 4.0* r / n;
}

int main(void)
{
printf("%1.9f\n", montecarlo(10));
printf("%1.9f\n", montecarlo(100));
printf("%1.9f\n", montecarlo(1000));
printf("%1.9f\n", montecarlo(10000));
printf("%1.9f\n", montecarlo(100000));
printf("%1.9f\n", montecarlo(1000000));
printf("%1.9f\n", montecarlo(10000000));
printf("%1.9f\n", montecarlo(100000000));
printf("%1.9f\n", montecarlo(1000000000));

return 0;