HDU 1001 Sum Problem

Posted 2020-08-12

 

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

题意：输入n，求1到n的和

注意：可以用求和公式，int会溢出，每个答案后要有一个空行

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