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我正在为 CS 课程制定税收计划。我在java中使用neatbeans和编程。我是编程新手。我的代码似乎正在工作，但是当我从我的 JComboBox 中选择“单一”以外的选择时，数学并没有改变它应该的方式。它继续使用“单一”选择中的数学。我想知道如何解决这个问题。另外，有一个随机的 2000 美元似乎在数学中浮动，所以我的计算有问题，但对于我的生活，我无法弄清楚是什么。当用户输入一个较低的 ' taxable美元错了。如果有人能看一眼我的代码并帮助我，我将不胜感激。PS，因为我是在调试程序，所以只填写了“单身”和“夫妻共同备案”。

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;

public class IncomeTax2 extends JFrame implements ItemListener
{

    private JTextField jtfIncome;
    private JTextField jtfTax;
    private JButton jbCalculate;
    private JComboBox jcb;
    private JLabel info;
    private String[] fsChoice =
    {
        "", "Single", "Married filing jointly", "Married filing separately",
        "Head of Household"
    };
    int income;
    double tax;
    private String filingStatus;

    public static void main(String[] args)
    {
        JFrame frame = new IncomeTax2();
        frame.pack();
        frame.setTitle("Income Tax Calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public IncomeTax2()
    {
        JPanel p = new JPanel();
        p.setLayout(new GridLayout(3, 2, 5, 5));
        p.setBorder(new EmptyBorder(5, 5, 5, 5));
        p.add(jtfIncome = new JTextField(8));
        p.add(jcb = new JComboBox(fsChoice));
        p.add(info = new JLabel("Enter taxable income "
                + "than pick filing status"));
        p.add(jbCalculate = new JButton("Calculate"));
        p.add(jtfTax = new JTextField(16));
        jtfTax.setEditable(false);
        setLayout(new BorderLayout());
        jtfTax.setHorizontalAlignment(JTextField.RIGHT);
        add(p, BorderLayout.CENTER);

        jtfIncome.addKeyListener(new KeyAdapter()
        {
            public void keyTyped(KeyEvent e)
            {
                char c = e.getKeyChar();
                if (!(Character.isDigit(c) || (c == KeyEvent.VK_BACK_SPACE)
                        || c == KeyEvent.VK_DELETE || c == KeyEvent.VK_ENTER))
                {
                    Toolkit.getDefaultToolkit().beep();
                    System.out.println("User must enter a digit.");
                    e.consume();
                }
            }
        });

        jcb.addItemListener(this);

        jbCalculate.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                calculate();
            }
        });
    }

    public void itemStateChanged(ItemEvent e)
    {
        income = Integer.parseInt(jtfIncome.getText());

        if (e.getStateChange() == ItemEvent.SELECTED)
        {
            filingStatus = (String) jcb.getSelectedItem();
            System.out.println(filingStatus);
            switch (filingStatus)
            {
                case "Single":
                    if (income <= 8350)
                    {
                        tax = income * 0.10;
                    }
                    if (income >= 8351 && income <= 33950)
                    {
                        tax = income * 0.15;
                    }
                    if (income >= 33951 && income <= 82250)
                    {
                        tax = income * 0.25;
                    }
                    if (income >= 82251 && income <= 171550)
                    {
                        tax = income * 0.28;
                    }
                    if (income >= 171551 && income <= 372950)
                    {
                        tax = income * 0.33;
                    } else
                    {
                        tax = income * 0.35;
                    }
                    break;

                case "Married filing jointly":
                    if (income <= 16700)
                    {
                        tax = income * 0.10;
                    }
                    if (income >= 16701 && income <= 67900)
                    {
                        tax = income * 0.15;
                    }
                    if (income >= 67901 && income <= 137050)
                    {
                        tax = income * 0.25;
                    }
                    if (income >= 137051 && income <= 208850)
                    {
                        tax = income * 0.28;
                    }
                    if (income >= 208851 && income <= 372950)
                    {
                        tax = income * 0.33;
                    } else
                    {
                        tax = income * 0.35;
                    }
                    break;
            }
        }
    }

    public void calculate()
    {
        jtfTax.setText((int) (tax - 2000) + "");
    }

}
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1 回答 1

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我收到错误，例如，输入 4000 税为 1400，这是 4000 的 35%，所以它看起来像是 if 的问题。您可以通过两种方式解决此问题，第一种是更改 if

if (income <= 8350){
    tax = income * 0.10;
    break;
}

在每一个（不要）中，另一个选择只是放一个

else if (income > 372950)

而不是最后的 else 。这解决了您遇到的奇怪的 2000 美元问题。

于 2014-03-20T20:37:09.900 回答