HDOJ-1001 Sum Problem

Sum Problem Time Limit: 1000/500 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 559426    Accepted Submission(s): 141821   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   Author DOOM III   Recommend We have carefully selected several similar problems for you:  1002 1090 1003 1091 1004

Tip:

1、注意输出格式（两个换行符）

但是我还是wrong answer了

2、正确的为把int sum=0;放进while循环里面

多组输入,每次sum都是0啊啊啊啊啊

#include <iostream>
using namespace std;

int main() {
	int a;
	while(cin>>a){
		int sum=0;//多组输入,每次sum都是0啊啊啊啊啊 
		for(int i=1;i<=a;i++){
			sum=sum+i;
		}
		cout<<sum<<endl<<endl;
	}
	
	return 0;
}