Sum Problem-hdu-1001

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

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int n,sum;
    while(scanf("%d",&n)!=EOF)//多次输入
    {
        sum=0;//放入循环体内，保证每次sum都被清0
        while(n)//当n！=0时，执行循环
        {
            sum+=n;//累加
            n=n-1;
        }
        printf("%d\n\n",sum);//输出结果
    }
return 0;
}