Question

我是Java的新手，在创建一个程序打印彩票的6个随机数时，我收到ArrayIndexOutOfBounds错误，我无法弄清楚如何修复。这就是我所拥有的。

import java.util.Random;

public class DebugMeOne {

    static int[] lottoNumbers = new int[6];

    public static void main(String[] args)
    {
        generateNumbers();
        printNumbers();
    }

    private static void generateNumbers()
    {
        int ticketNumber;
        Random generateRandomNumber = new Random();

        for (int count = 0; count < lottoNumbers.length + 1; count++)
        {
            ticketNumber = 1 + generateRandomNumber.nextInt(59);
            lottoNumbers[count] = ticketNumber;
       }
    }

    private static void printNumbers()
    {
       for (int count = 0; count < lottoNumbers.length + 1; count++)
        {
           if (count < 5)
               if (count == 4)
                   System.out.print(lottoNumbers[count]);
               else
                    System.out.print(lottoNumbers[count] + ", ");
           else
               System.out.println("\nPower Ball: "
                                    + lottoNumbers[count]);
        }
    }
}

我还有另一个程序，我必须为同样的事情创建，只是一点点不同的代码。我也遇到了错误：

public class Lottery {

    static ArrayList<Integer> lottoNumbers = new ArrayList<Integer>();
    static int MAX_NUMBERS = 6;

    public static void main(String[] args)
    {
        generateNumbers();
        printNumbers();
    }

    private static void generateNumbers()
    {
        int ticketNumber;
        Random generateRandomNumber = new Random();

        for (int count = 0; count < MAX_NUMBERS; count++)
        {
            ticketNumber = 1 + generateRandomNumber.nextInt(59);
            lottoNumbers.add(new Integer(ticketNumber));
        }
    }

    private static void printNumbers()
    {
        int count = 0;
        for( Integer number : numbers )  // enhanced for loop
        {
           if (count < 5)
               if (count == 4)
                   System.out.print(number);
               else
                    System.out.print(number + ", ");
           else
           {
               System.out.println("\nPower Ball: " + number);
               count++;
           }
        }
    }
}

在此我收到此错误：

Exception in thread "main" java.lang.RuntimeException: Uncompilable source code
cannot find symbol
  symbol:   variable numbers
  location: class debugmetwo.DebugMeTwo
    at debugmetwo.DebugMeTwo.printNumbers(DebugMeTwo.java:52)
    at debugmetwo.DebugMeTwo.main(DebugMeTwo.java:34)
Java Result: 1

Answer 1

你的循环条件应该是：

for (int count = 0; count < lottoNumbers.length; count++)

lottoNumbers的有效索引来自0到lottoNumbers.length - 1。

Answer 2

您的for循环次数超过了数组length。 for循环都应该像

一样运行

for (int count = 0; count < lottoNumbers.length; count++)

此外，您不应该对length比较中使用的count值（5,4）进行硬编码以打印逗号。使用length属性

for (int count = 0; count < lottoNumbers.length; count++)
 {
   if (count < lottoNumbers.length - 1) {
       System.out.print(lottoNumbers[count]);
       System.out.print(count == lottoNumbers.length - 2 ? "" : ", ");
   } else {
       System.out.println("\nPower Ball: "
                            + lottoNumbers[count]);
   }
 }

ArrayIndexOutOfBounds错误抽奖程序/无法编译的源代码错误

2 个答案: