C/C++编程学习 - 第13周 ⑨ Sum Problem

题目链接

题目描述

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

思路

题意就是，从 1 到 n 累加求和，输出和。注意输出的格式。

C++代码：

#include<bits/stdc++.h>
using namespace std;
int main()
{
    
    
	int n;
	while(cin >> n)
	{
    
    
		long long sum = 0;
		for(int i = 0; i <= n; i++)
			sum += i;
		cout << sum << endl << endl;
	}
	return 0;
}