java - 为什么 while() 能创造魔力？

Question

我正在编写一个程序来查找从 100 到 999 的阿姆斯特朗数字。如果我将数字作为输入程序工作，但如果我使用 while 循环检查数字，它会说每个数字都不是阿姆斯特朗数字。我不明白为什么。

这是代码:

 package armstrong;

 //import java.util.Scanner;

 public class Armstrong {


    public static void main(String[] args) {
        int n, sum = 0, temp, remainder, digits = 0;

        //Scanner in = new Scanner(System.in);
        //System.out.println("Input a number to check if it is an Armstrong number");      
        //n = in.nextInt();
        n = 100;
        while (n <= 999) {
            temp = n;

            // Count number of digits

            while (temp != 0) {
                digits++;
                temp = temp / 10;
            }

            temp = n;

            while (temp != 0) {
                remainder = temp % 10;
                sum = sum + power(remainder, digits);
                temp = temp / 10;
            }

            if (n != sum) System.out.println(n + " is not an Armstrong number.");
            else System.out.println("Armstrong number:" + n);

            n++;

        }
    }

    static int power(int n, int r) {
        int c, p = 1;

        for (c = 1; c <= r; c++)
        p = p * n;

        return p;
    }
 }

Answer 1

您应该在循环中初始化数字，总和为零，例如:

while (n <= 999) {
    digits = 0;
    sum = 0
    ...
}