计算阶乘和 递归

#include <iostream>
using namespace std;
int sum = 0;
int fact(int k)
{
	if (k == 0 || k == 1)
		return 1;
	else
		return k * fact(k - 1);
}
int main()
{
	int n;
	cin >> n;
	for (int i = 1; i <= n; i++)
		sum += fact(i);
	cout << sum;
	return 0;
}