题目：
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
解析：
1.不能使用等差数列求和公式
2.输出格式有两个换行符
#include <stdio.h> #include <stdlib.h> int main() { int n; while(scanf("%d",&n)!=EOF){ int sum=0; for(int i=1;i<=n;i++) { sum=sum+i; } printf("%d\n\n",sum); } return 0; }
