杭电 1001

Problem Description

Hey, welcome to HDOJ(Hangzhou Dianzi University Online Judge).

In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.

 

Input

The input will consist of a series of integers n, one integer per line.

 

Output

For each case, output SUM(n) in one line, followed by a blank line. You may assume the result will be in the range of 32-bit signed integer.

 

Sample Input

1100

 

Sample Output

1
5050
特别注意题目要求即可
#include <iostream>using namespace std;int main(){int n;int sum;while(cin>>n){sum=0;for(int i=1;i<=n;i++){sum+=i;}cout<<sum<<endl;cout<<endl;}return 0;}