求和问题 Sum Problem

Sum Problem

题目—from hdoj

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

分析

程序

import java.util.Scanner;public class Main {    public static void main(String[] args) {        Scanner sc = new Scanner(System.in);        while (sc.hasNextInt()) {            int a = sc.nextInt();            int sum = 0;            for (int i = 1; i <= a; i++) sum += i;            System.out.println(sum);            System.out.println();        }    }}