循环-02. 计算圆周率(15)

#include <stdio.h>
int main(void) {
double sum = 1, item = 1, fact = 1, denominator = 1;
double eps;
int i = 1;
scanf("%lf", &eps);
while(item >= eps) {
fact *= i;
denominator *= (2 * i + 1);
item = fact / denominator;
sum += item;
++i;
}
printf("%.6f\n", 2 * sum);
return 0;
}