1001 Sum Problem

1001 Sum Problem

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

1
100

Sample Output

1
5050

代码

#include
using namespace std;

int main()
{
     int i, n, sum;
     while(cin>>n)
     {
            sum=0;
            for(i=1; i<=n; i++)
                   sum+=i;
            cout<<sum<<endl<<endl;
     }
     return 0;
}