java - 需求标识符是什么意思？

Question

我正在尝试制作一个程序来跟踪热狗摊位以及他们卖了多少热狗，在制作它时我有两个文件，这是第一个文件，它指向括号，我不确定是什么这意味着那里需要一个标识符。这是代码

public class HotDogStand
{
    private String nameHotDogStand;
    private String IDnumber;
    private int hotDogsSold;

    public HotDogStand(String nameHotDogStand, String IDnumber, int hotDogsSold)
    {
        this.nameHotDogStand = nameHotDogStand;
        this.IDnumber = IDnumber;
        this.hotDogsSold = hotDogsSold;
    }

    public String getNameHotDogStand()
    {
        return nameHotDogStand;
    }

    public void setNameHotDogStand(String nameHotDogStand)
    {
        this.nameHotDogStand = nameHotDogStand;
    }

    public String getIDnumber()
    {
        return IDnumber;
    }

    public void setIDnumber(String IDnumber)
    {
        this.IDnumber = IDnumber;
    }

    public int getHotDogsSold()
    {
        return hotDogsSold;
    }

    public void setHotDogsSold(int HotDogsSold)
    {
        this.hotDogsSold = hotDogsSold;
    }

    public void SetJustSold(int hotDogsSold)
    {
        hotDogsSold++;
        totalHotDogsSold++;
    }

    public void showHotDogsSold(int hotDogsSold)
    {
        System.out.print("The number of hot dogs sold is: " + hotDogsSold);
    }

    private static int totalHotDogsSold;

    public  String showTotalHotDogsSold()
    {
        return ("The total number of hot dogs sold is: " + totalHotDogsSold);
    }

    public String toString()
    {
        return "The total number of hot dogs sold is: " + totalHotDogsSold;
    }

    public HotDogStand(HotDogStand otherHotDogStand)
    {
        nameHotDogStand = otherHotDogStand.nameHotDogStand;
        hotDogsSold = otherHotDogStand.hotDogsSold;
        IDnumber = otherHotDogStand.IDnumber;
    }

    public String toString()
    {
        return("Total sold =" + (one.getNumSold() + two.getNumSold() + 
                                 three.getNumSold()) + "\n");
    }

    one.SetJustSold();
    two.SetJustSold();
    three.SetJustSold();
}

还有我不确定第二个文件的第二个问题。我是否需要将“return”放在公共(public)下方但名称HotDogStand上方，还是有其他问题？

public class TheHotDogStands
{
    public static void main(String[]args)
    {
        HotDogStand one = new HotDogStand ("Bob's hotdog stand" , "0081"  , "5");
        HotDogStand two = new HotDogStand ("Chris's hotdog stand" , "4591" , "3");
        HotDogStand three = new HotDogStand ("Matt's hotdog stand" , "1171" , "10");


       System.out.println(one.getName + one.getID + one.getNumSold);
       System.out.println(two.getName + two.getID + two.getNumSold);
       System.out.println(three.getName + three.getID + three.getNumSold);
       System.out.println("Total sold for all stands = " + (one.getNumSold() + 
                                       two.getNumSold() + three.getNumSold()));

    }

    public one(one aOne)
    {
        nameHotDogStand = aNameHotDogStand;
        IDnumber = aIDnumber;
        hotDogsSold = aHotDogsSold;
    }
}

我对编程还是个新手，遗憾的是我们的书不太擅长解释事情，我的老师说选择这本书是因为它适用于他们教授的两门类(class)，所以有没有任何好的网站提供指南，可能有一些好的例子吗？我有时确实会找到一些，但它们似乎是从不同的来源和网站传播的。

感谢您提供任何信息。

Answer 1

在第一个中，您在任何方法之外都有这些行:

one.SetJustSold();
two.SetJustSold();
three.SetJustSold();

它们需要位于方法或静态初始化 block 中。

在第二个中，您从未声明 one() 的返回类型。