杭电1001 Sum Problem

#include <iostream>using namespace std;/*//此题难点是需要两次换行符int main(){    int n;    int sum = 0;    while (cin>>n)    {        for (int i=0; i<= n;i++)        {            sum += i;        }        cout << sum <<"\n"<<endl;        sum = 0;    }    return 0;}*/