java - 在计算 1+2+3+4...+n 时需要帮助吗？

Question

所以我被指派编写一个程序，该程序询问一个数字 (n)，然后像这样进行加法:1+2+3+4...+n 并打印加法

虽然我总是收到错误的数字，但无法弄清楚哪里出了问题？

import java.util.Scanner;

public class LukusarjanSumma {

    public static void main(String[] args) {
        Scanner reader = new Scanner(System.in);
        int addition = 0;
        System.out.println("Where to?");
        int n = Integer.valueOf(reader.nextLine());
        while (addition <= n){
            addition += addition;
            addition ++;
        } System.out.println("Total is " + addition);
    }
}

Answer 1

你需要区分

• 总结所有的加法

• 一个 counter 值递增的索引:1,2,3...n

  int addition = 0;
  int counter = 0;
  System.out.println("Where to?");
  int n = Integer.parseInt(reader.nextLine());
  while (counter <= n) {
      addition += counter;
      counter++;
  }
  System.out.println("Total is " + addition);
  

但是使用for循环会更容易，这样更符合逻辑

int n = Integer.parseInt(reader.nextLine());
for (int i = 0; i <= n; i++) {
    addition += i;
}