java - 使用 do-while 循环并找出两个数字之间的差异

Question

我正在尝试创建一个程序，随机生成 1 到 10,000 之间的数字，然后将该数字除以 100 以创建另一个数字，然后用户应输入该数字的更改。 (67.48 是 b x 20、5、1、四分之一等的数量)...如果用户在答案中输入了错误的数字，程序应该显示他们的答案与随机数之间的差异。词汇表中没有任何关于差异或发现差异的内容……而且我从来没有做过像我们目前正在失去的那样广泛的 do-while 循环。我需要一些帮助来找出我做错了什么。

// ---------1---------2---------3---------4---------5---------6---------7
// 1234567890123456789012345678901234567890123456789012345678901234567890
import java.util.Scanner;
import java.util.Random;

public class ChangeGame
{
   public static void main(String[] args)
   {
      int low = 1;
      int max = 10000;
      int twentyDollars = 0;
      int tenDollars = 0;
      int fiveDollars = 0;
      int oneDollar = 0;
      int quarters = 0;
      int dimes = 0;
      int nickels = 0;
      int pennies = 0;
      Random random = new Random();
      int randomNumber = random.nextInt(max - low + 1);
      double randomNumber1 = (randomNumber /100.0); 

      Scanner keyboard = new Scanner(System.in);

      do  
      {
         System.out.println("Enter the change for " + randomNumber1);
         System.out.println("Twenties: "); 
         twentyDollars = keyboard.nextInt();
         while( twentyDollars < 0 );
         {
            System.out.println( "** Invalid Amount **\n" +
               "Twenties: " );
            twentyDollars = keyboard.nextInt();
         }

         System.out.println("Enter the change for " + randomNumber1);
         System.out.println("Tens: "); 
         tenDollars = keyboard.nextInt();
         while( tenDollars <= 1 )
         {
            System.out.println( "** Invalid Amount **\n" +
               "Tens: " );
            tenDollars = keyboard.nextInt(); 
         }

         System.out.println("Enter the change for " + randomNumber1);
         System.out.println("Fives: "); 
         fiveDollars = keyboard.nextInt();
         while( fiveDollars <= 1 )
         {
            System.out.println( "** Invalid Amount **\n" +
               "Fives: " );
            fiveDollars = keyboard.nextInt();
         }

         System.out.println("Enter the change for " + randomNumber1);
         System.out.println("Ones: "); 
         oneDollar = keyboard.nextInt();
         while( oneDollar <= 4 )
         {
            System.out.println( "** Invalid Amount **\n" +
               "Ones: " );
            oneDollar = keyboard.nextInt();
         }

         System.out.println("Enter the change for " + randomNumber1);
         System.out.println("Quarters: "); 
         quarters = keyboard.nextInt();
         while( quarters <= 3 )
         {
            System.out.println( "** Invalid Amount **\n" +
               "Quarters: " );
            quarters = keyboard.nextInt();
         }

         System.out.println("Enter the change for " + randomNumber1);
         System.out.println("Dimes: "); 
         dimes = keyboard.nextInt();
         while( dimes <= 2 )
         {
            System.out.println( "** Invalid Amount **\n" +
               "Dimes: " );
            dimes = keyboard.nextInt();
         }

         System.out.println("Enter the change for " + randomNumber1);
         System.out.println("Nickels: "); 
         nickels = keyboard.nextInt();
         while( nickels <= 1 )
         {
            System.out.println( "** Invalid Amount **\n" +
               "Nickels: " );
            nickels = keyboard.nextInt();
         }

         System.out.println("Enter the change for " + randomNumber1);
         System.out.println("Pennies: "); 
         pennies = keyboard.nextInt();
         while( pennies <= 4 )
         {
            System.out.println( "** Invalid Amount **\n" +
               "Pennies: " );
            pennies = keyboard.nextInt();
         }

      while( difference != 0);
         {
            System.out.println("Incorrect by: ");
         }
   } 
}​

Answer 1

这里有一个错误(不确定这是否是唯一的一个):

改变

     while( twentyDollars < 0 );
                               ^
     {
        System.out.println( "** Invalid Amount **\n" +
           "Twenties: " );
        twentyDollars = keyboard.nextInt();
     }

至

     while( twentyDollars < 0 )
     {
        System.out.println( "** Invalid Amount **\n" +
           "Twenties: " );
        twentyDollars = keyboard.nextInt();
     }

while( twentyDollars < 0 );可能是无限循环(如果 twentyDollars < 0 最初)。

编辑:

这里还有另一个错误:

  while( difference != 0);
  {
      System.out.println("Incorrect by: ");
  }

看起来像这样while意味着结束 do-while 循环。如果是这样的话，您就错过了 } :

}
while (difference != 0);

目前还不清楚以下内容

{
    System.out.println("Incorrect by: ");
}

是打算做的。它与前面的 while 语句没有关系。