java - 运行时异常 : Uncompilable source code - cannot find symbol

Question

我是 Java 新手，正在编写一个程序来打印彩票的 6 个随机数字。我收到错误，

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

import java.util.Random;
import java.util.ArrayList;

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 )  
        {
           if (count < 5)
               if (count == 4)
                   System.out.print(number);
               else
                    System.out.print(number + ", ");
           else
           {
               System.out.println("\nPower Ball: " + number);
               count++;
           }
        }
    }
}

Answer 1

您的代码存在编译错误，因此程序无法运行:变量 numbers 未在任何地方定义。如果您想循环生成的数字，请使用由 generateNumbers 方法填充的 lottoNumbers。您还应该在打印每个元素后增加 count++ (我强烈建议您在 if 语句之后始终使用大括号以避免错误):

int count = 0;
for (Integer number : lottoNumbers) {
    if (count < 5) {
        if (count == 4) {
            System.out.print(number);
        } else {
            System.out.print(number + ", ");
        }
    } else {
        System.out.println("\nPower Ball: " + number);
    }
    count++;
}