杭州电子科技大学 ACM 1001 Sum Problem

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

解题源代码

#include<stdio.h>
int main(){
	int n,i;
	int s;
	while(scanf("%d",&n)!=EOF){
		s=0;
		i=1;
		while(i<=n)
			s+=i++;
		printf("%d\n\n",s);
	}
	return 0;
}