java - 阿姆斯特朗数java代码有问题

Question

我用 java 为学校编写了一段代码，用于验证数字是否为阿姆斯特朗数字。我对其进行了编程，使其运行多次，直到用户输入 0，此时程序将终止。我有两个问题。

1. 该代码仅在第一次运行，如果用户第一次输入 371(阿姆斯壮数字)，它会运行，但之后返回该数字不是阿姆斯壮数字。

2. 当用户输入0时，它仍然显示是否是阿姆斯特朗数的语句，这是我不希望的。

这是代码:

import java.util.Scanner; //import Scanner for user input   

public class Ch6Project {    

    public static void main(String[] args) {  

        int userNum, totalValue = 0, num, numLength; //declare variables that will be used
        String suserNum; //declare user input variable
        Scanner input = new Scanner(System.in); //declare a Scanner

        System.out.println("Welcome to the Armstrong Number Program."); //description
        System.out.println("\nTo calculate an Armstrong number: ");
        System.out.println("\t 1. Cube each digit of the number.");
        System.out.println("\t 2. Take the sum of these cubes.");
        System.out.println("\t 3. If the sum equals the number, it is an Armstrong Number.");
        System.out.println("\t e.g. 3^3 + 1^3 + 7^3 = 317");

        do {
            System.out.print("\nEnter a whole number (0 to quit): ");
            suserNum = input.nextLine(); //collect user input
            userNum = Integer.parseInt(suserNum); //parse user input
            numLength = suserNum.length(); //calculate length of user input

            for (int i = numLength; i > 0; i--) { //create loop to run for n times 
                num = Integer.parseInt(suserNum.substring(numLength - 1, numLength)); //get last digit of number
                totalValue += Math.pow(num, 3); //cube a digit 
                numLength--; //subtract userNum by 1 to get the rest of the digits
            }

            if (totalValue == userNum) { //if total value equals user input, it is Armstrong #
                System.out.println("Your number is an Armstrong number.");
            } else { //if total value does not equal user input, it is not an Armstrong #
                System.out.println("Your number is not an Armstrong number.");
            }

        } while (userNum != 0); //run loop until user input == 0
        input.close(); //close user input

    }
}

Answer 1

更改您的代码，使其在输入userNum后立即中断

例如

userNum = Integer.parseInt(suserNum); //parse user input
if (userNum == 0) {
   break;
}

那么你也可以将循环更改为无限循环

while (true) {
   // your code
}