java - 在我的程序中找不到这个错误

Question

import java.util.Scanner;
import java.util.Random;

public class SlotMachine
{
   public static void main(String []args)
   {
      Scanner input = new Scanner(System.in);
      Random randomGen = new Random();

      int start = 10;

      System.out.println("Welcome to the Slot machine!");
      System.out.println("You have "+ start);
      System.out.println("Choose one of the following menu options:");
      //==============================
      // MENU
      //==============================
      int menu = 2;

      while (menu >= 1 && menu <= 2)
      {
         System.out.println("1) Play the slot machine.");
         System.out.println("2) Cash out.");
         menu = input.nextInt();

         if (menu == 1)
         {

            System.out.print("The slot machine shows: ");

            //================================================
            //GENERATE A RANDOM NUMBER BTWEEN 0-10 INCLUSIVE
            //================================================
            for(int i = 0; i < 3; i++)
            {

               int randomNum = randomGen.nextInt(10);
               System.out.print(randomNum);
            }

            if (randomNum < 100)
            {
               System.out.println("Sorry you don't win anything!!");
            }


            else if ( randomNum >= 1 && randomNum < 1000)
            {

            }

            //===========================================
            // KEEPING COUNT OF  HOW MANY TIMES PLAYED
            // ==========================================
            int count = 0; // keeps count of how many times you play
            int amountLeft = 0;
            while (count <= menu)
            {
               count += (menu*0.25);
               amountLeft = start - count;
            }

            System.out.println("You have" + amountLeft);

         }
         if (menu == 2)
         {
            System.out.println("Thank you for playing ");
         }

         if (menu < 1 || menu > 2)
         {
            System.out.println("invalid range of numbers....  PLEASE ENTER 1 OR 2!!!");
         }
         break;
      }
   }
}

我有一个错误提示 randomNum cannot be resolved。我以为我声明了这个变量并初始化了它。为什么它一直给我错误？

我的问题的第二部分是如何解决这个问题？这个程序是老虎机。这是输出示例:

Welcome to the slot machine! 
You have $10.00.
Choose one of the following menu options:
1) Play the slot machine.
2) Cash out.

1

The slot machine shows 046. 
Sorry you don't win anything.

You have $9.75.
Choose one of the following menu options:
1) Play the slot machine.
2) Cash out.

1

The slot machine shows 933. 
You win 50 cents!

You have $10.00.
Choose one of the following menu options:
1) Play the slot machine.
2) Cash out.

如何确定随机生成的数字中相同的两个数字来确定某人是否中奖，例如 433 或 111 或 224？

Answer 1

虽然我不明白你问题的第二部分，但第一部分很简单:

    //================================================
    //GENERATE A RANDOM NUMBER BTWEEN 0-10 INCLUSIVE
    //================================================
    for(int i = 0; i < 3; i++)
    {

        int randomNum = randomGen.nextInt(10);
        System.out.print(randomNum);
    }

    if (randomNum < 100)

您已在 for 范围内声明了 randomNum。你应该这样做:

    //================================================
    //GENERATE A RANDOM NUMBER BTWEEN 0-10 INCLUSIVE
    //================================================

    int randonNum = 0; // declare the variable & initialize it
    for(int i = 0; i < 3; i++)
    {
        randomNum = (randomNum * 10) + randomGen.nextInt(10);
        System.out.print(randomNum);
    }

    if (randomNum < 100)

更新:我想我也想出了第二个问题。您需要确定随机数中是否至少有两个相等的数字。以下是您的操作方法(我相信还有一些不错的数学方法 :)):

int digitA = randomNum % 10;
int digitB = (randomNum / 10) % 10;
int digitc = (randomNum / 100) % 10;

if(digitA == digitB || digitA == digitC || digitB == digitC) {
    // matches
} else {
    // no match
}

请注意，因为我看到您将数字限制在 100 到 999 之间，所以我只假设三位数，并帮助您单独解决这个问题，您应该自己解决剩下的问题!我不想解决你的作业，但我确实想为你指明正确的方向。

*我更新了答案以反射(reflect) yi_H 的建议。*