杭电OJ第1001题，Sum Problem

题目要求：

        Problem Description
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. 
//注意，此处要求每个输出占一行，之后还需空一行，即输出需要两个“\n”
 
Sample Input
1
100
 
Sample Output
1
5050

代码实现：

        #include<stdio.h>
 
int main(int argc, char **argv)
{
    int i,n,s;
    i=0,n=0,s=0;
    while(scanf("%d",&n)!=EOF)
    {
        for(i=0; i<=n; i++)
        {
            s+=i;
        }
        // 此处两个“\n”为题目要求的，否则会出现Presentation Error 
        printf("%d\n\n",s);    
        s=0;
    }
    return 0;
}