Question

我试图创造条件

如果发票号码小于1000，请强制将发票号码设为0。
如果月份字段小于1或大于12，则强制将月份字段设为0。
如果日期字段小于1或大于31，则强制将日期字段设为0。
如果年份字段小于2011年或大于2017年，请将年份字段强制为0。

但是当我尝试运行它时，它会强制所有字段为0，即使我为变量设置了正确的值：

Please type your invoice number: ...1111
What month is the balance due?(Choose from 1-12)... 1
What day is the balance due?(Choose from 1-31).... 12
What year is the balance due? (Choose from 2011-2017) ....2011
Your invoice number is 0 and your balance due is on 0/0/0.

public class Invoice
{
    private int     inNum;
    private double  balDue;
    private int     m;
    private int     d;
    private int     yy;

    public Invoice ()
    {
        super();
        setInNum(inNum);
        getInNum();
        setBalDue(balDue);
        setM(m);
        setD(d);
        setYy(yy);

    }

    public int getInNum ()
    {
        return inNum;
    }

    public void setInNum (int inNum)
    {
        if (inNum < 1000)
            this.inNum = 0;
        else
            this.inNum = inNum;
    }

    public double getBalDue ()
    {
        return balDue;
    }

    public void setBalDue (double balDue)
    {
        this.balDue = balDue;
    }

    public int getM ()
    {
        return m;
    }

    public void setM (int m)
    {
        if (m < 1 || m > 12)
            this.m = 0;
        else
            this.m = m;
    }

    public int getD ()
    {
        return d;
    }

    public void setD (int d)
    {
        if (d < 1 || d > 31)
            this.d = 0;
        else
            this.d = d;

    }

    public int getYy ()
    {
        return yy;
    }

    public void setYy (int yy)
    {
        if (yy < 2011 || yy > 2017)
            this.m = 0;
        else
            this.yy = yy;
    }

    public void displayInfo ()
    {
        int inNum;

        int m, d, yy;
        Scanner keyboard = new Scanner(System.in);
        System.out.print("Please type your invoice number: ");
        inNum = keyboard.nextInt();
        System.out
                .print("What month is the balance due?(Choose from 1-12) ");
        m = keyboard.nextInt();
        System.out
                .print("What day is the balance due?(Choose from 1-31) ");
        d = keyboard.nextInt();
        System.out
                .print("What year is the balance due? (Choose from 2011-2017) ");
        yy = keyboard.nextInt();

        System.out.println("Your invoice number is " + getInNum()
                + " and your balance due is on " + getM() + "/" + getD()
                + "/" + getYy() + ".");

    }

    public static void main (String[] args)
    {
        Invoice invoice = new Invoice();
        invoice.displayInfo();
    }

}

Answer 1

这是失败的，因为您在调用所有setter方法后调用了displayInfo。它需要先发生，否则制定者无所事事。

我认为在构造函数中调用这些setter方法是错误的。一旦你有了需要传递给它的值，你需要调用每一个。

因此，您输入的每个值都可能有一个局部变量，然后将其传递给setter

int invoiceNumber = keyboard.nextInt();
setInNumber(invoiceNumber);

所有其他领域的

等等。

Answer 2

你为这个班制作了所有那些漂亮的制定者并且没有使用它们！

Scanner keyboard = new Scanner(System.in);
System.out.print("Please type your invoice number: ");
setInNum(keyboard.nextInt());
System.out.print("What month is the balance due?(Choose from 1-12) ");
setM(keyboard.nextInt());
System.out.print("What day is the balance due?(Choose from 1-31) ");
setD(keyboard.nextInt());
System.out.print("What year is the balance due? (Choose from 2011-2017) ");
setY(keyboard.nextInt());

System.out.println("Your invoice number is " + getInNum() +  " and your balance due is on " + getM() + "/" + getD() + "/" + getYy() + ".");

逻辑/语义错误

2 个答案: