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.
计算一连串整数的累积和
Input
The input will consist of a series of integers n, one integer per line.
输入由一系列的整数组成,每行接受一个整数输入(代表 n)
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.
对于每一种情况,SUM在空白行之后的单独的一行输出。假定所有的结果都在有符号的32位整型范围之内
Sample Input
1
100
Sample Output
1
5050
import java.util.Scanner; public class Main{ public static void main(String[] args) { Scanner scan = new Scanner(System.in); long i,sum,n; while(scan.hasNextLong()) { n = scan.nextLong(); sum = 0; for(i=1; i<=n;i++) { sum = sum+i; } System.out.println(sum); System.out.print("\r\n"); } }