C++ 计算阶乘之和

#include using namespace std;

int factorial(int n) { if (n == 0) return 1; return n * factorial(n-1); }

int main() { int n; cin >> n;

int sum = 0; for (int i = 1; i <= n; i++) { sum += factorial(i); }

cout << sum << endl; return 0; }