HDOJ2_Sum Problem

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.

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