【 OJ 】 HDOJ1001 n!求和 [ 2 ]

这题没什么蛋疼了，还好2-3次也算AC了

# include<iostream> using namespace std; int sum(int n) { int sum = 0; for (int i = 1; i <= n; ++i) sum += i; return sum; } int main(void) { int n; while (cin >> n) { cout << sum(n) << endl<<endl; } return 0; }