java - 我需要帮助完成作业

Question

我已经在这个程序上工作了大约 3 周，但无法找出我的错误。我必须使用两个公共(public)类:1) validateLength(Number) 和 2) convertIntegerToWords(Number)。我的问题是，一旦用户输入他们的整数，我的循环就会永远持续下去。系统将要求输入整数、用户输入、系统输出太长或继续转换为 convertIntgerToWords。我的代码在下面

import java.util.Scanner;
public class Project2 {

    public static void main(String [] args) {
        //Main Method//

        //Create a Scanner//
        Scanner input = new Scanner(System.in);

        //Enter an Integer//   
        System.out.print(" What is your integer ? ");
        int Number= input.nextInt(); 
        while (Number >= 0) {
            if (Number != 0)
                validateLength(Number);
            else if(Number == 0) {
                System.out.print( "Thank you for playing! " + "Good bye! ");    
                break;
            }
        }   
    }

    //Next Method//
    public static boolean validateLength(int userNum) {
        String Number = "" + userNum;
        while (userNum >= 0) {
            if (userNum < 10) 
                convertIntegerToWords(userNum);
            else if (userNum > 9){
                System.out.print("Your integer is too long !");
                break;
            }
        }
    }
    //End of validate//

    //Final Method//
    public static String convertIntegerToWords(int Number) {
        if (Number == 1)
            System.out.println("Your integer " + Number + "is written out as one");
        else if (Number == 2) 
            System.out.println("Your integer " + Number + "is written out as two");
        else if (Number == 3) 
            System.out.println("Your integer " + Number + "is written out as three");
        else if (Number == 4) 
            System.out.println("Your integer " + Number + "is written out as four");
        else if (Number == 5) 
            System.out.println("Your integer " + Number + "is written out as five");
        else if (Number == 6) 
            System.out.println("Your integer " + Number + "is written out as six");
        else if (Number == 7) 
            System.out.println("Your integer " + Number + "is written out as seven");
        else if (Number == 8) 
            System.out.println("Your integer " + Number + "is written out as eight");
        else if (Number == 9) 
            System.out.println("Your integer " + Number + "is written out as nine");
            return Number + "";
        }
    }
}

Answer 1

你需要移动

Number = input.nextInt();

while 循环内部。这是典型的习语(也添加了其他清理):

public static void main(String[] args)
{
    Scanner input = new Scanner(System.in);
    
    // Enter an Integer//
    System.out.print(" What is your integer ? ");
    int Number;
    while ((Number = input.nextInt()) >= 0)
    {
        if (Number == 0)
        {
            System.out.print("Thank you for playing! " + "Good bye! ");
            break;
        }
        
        validateLength(Number);
    }
}

---

编辑

if the user enters 0 then yes the program terminates. However if the user enters an integer 1-9, the program should spell out the integer in words (ie 1 is written out as one). It does this but it loops infinite. Same as if the user enters an integer larger than 9 it reports that the "YOur integer is too big, enter another integer" This however, repeats on the same line over and over.

那是因为 validateLength() 中的 while 循环。试试这个(同时注意其他代码清理):

public class ScannerDemo
{
    private static void convertIntegerToWords(int num)
    {
        String message = null;
        if (num > 9)
        {
            message = "Your integer is too long!";
        }
        else if (num > 0)
        {
            message = "Your integer " + num + " is written out as ";
            String numString = "";
            
            switch (num)
            {
                case 1:
                    numString = "one"; break;
                case 2:
                    numString = "two"; break;
                case 3:
                    numString = "three"; break;
                case 4:
                    numString = "four"; break;
                case 5:
                    numString = "five"; break;
                case 6:
                    numString = "six"; break;
                case 7:
                    numString = "seven"; break;
                case 8:
                    numString = "eight"; break;
                case 9:
                    numString = "nine"; break;
            }
            
            message += numString;
        }
        
        System.out.println(message);
    }
    
    private static int getNextNumber(Scanner s)
    {
        System.out.println("What is your integer?");
        return s.nextInt();
    }
    
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
        
        int number;
        while ((number = getNextNumber(input)) >= 0)
        {
            if (number == 0)
            {
                System.out.println("Thank you for playing! Good bye!");
                break;
            }
            
            convertIntegerToWords(number);
        }
    }
}

也是on github .