杭电1001

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

 

这一题主要是考研C语言初学者如何使用循环结构，当然还要注意followed by a blank line这句话，不然是ac不了的

 

#include<stdio.h> int main() { int n,i,a; while(scanf("%d",&n)!=EOF) { a=0; for(i=1;i<=n;i++) a=a+i; printf("%d\n\n",a);// 要多空出一行 } return 0; }