用C实现求阶乘之和（非递归实现）

这是是求阶乘和的非递归实现：

// methods1.c
#include <stdio.h>

long double Fn(int n);

int main(void)
{
    long double sum = 0;
    int i, n;
    i = n = 0;
    printf("Please input a number: \n");
    scanf("%d", &n);
    if (n > 1000 )
	printf("ERROR!The number is too large!\nPlease try again!(0~1000)\n");
    else if (n < 0)
	printf("ERROR!The number is invalid!\nPlease try again!(0~1000)\n");
    else
    {
	for (i = 0; i <= n; i++)
	    sum += Fn(i);
	printf("The %d factorial's sum is %Lf\n", n, sum);
    }

    return 0;
}

long double Fn(int n)
{
    int i = 1;
    long double temp = 1;
    if (n == 0)
	return 1;
    for (i = 1; i <= n; i++)
        temp = temp * i;
    return temp;
    
}