pi

#include <stdio.h>double numerator, denominator, pi;int main(){	numerator = 2;	denominator = 1;	pi = 1;	unsigned long long i, r;	for (r = 0; r < 4; r++)	{		for (i = 0; i <= 0xffffffff; i++)		{			pi *= numerator / denominator;			denominator += 2;			pi *= numerator / denominator;			numerator += 2;		}	}	printf("Pi = %.15f\n", pi * 2);	return 0;}