Sum Problem 重定向文件的使用

Sum Problem

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.

 

Sample Input

1
100 

 

Sample Output

1
​
5050

标准代码：

#include<stdio.h>
//#define LOCAL
int main(){
    /*
    #ifdef LOCAL
    freopen("input.txt","r",stdin);//需要创建input.txt，里面写入1和100。
    freopen("output.txt","w",stdout);
    #endif
    */注释的代码用作文本输入输出。
    int i,n,s;
    while(scanf("%d",&n)!=EOF)
    {
        s=0;
        for(i=1;i<=n;i++){
            s+=i;
        }
        printf("%d

",s); 
    }
    return 0;
}

• ACM需要的文本输入输出。重定向文件，具体请参考：freopen 使用 --重定向文件 

题目来源：http://acm.hdu.edu.cn/listproblem.php?vol=1