public Calculator() { super("Calculator"); this.setLocationRelativeTo(null);// set up window this.setResizable(false); this.setDefaultCloseOperation(EXIT_ON_CLOSE); this.setSize(600, 200); result = new JPanel(); answer = 0.0 ; show = new JLabel(Double.toString(answer), SwingConstants.RIGHT);// let the result at the right of the field result.add(show); JTextField input = new JTextField(Double.toString(answer));// setup the size of the text field input.setColumns(6); input.setHorizontalAlignment(JTextField.RIGHT); button = new JPanel(); button.setLayout(new GridLayout(1, 5)); CLR = new JButton("CLR");// add the buttons of calculation. add = new JButton("+"); minus = new JButton("-"); Multiply = new JButton("*"); divide = new JButton("/"); button.add(CLR); button.add(add); button.add(minus); button.add(Multiply); button.add(divide); CLR.addActionListener(e -> {// clear answer = 0.0; show.setText(Double.toString(answer)); field.setText(" "); }); add.addActionListener(e -> {// add number = field.getText(); if (!number.equals(null)) { double value = Double.parseDouble(number); answer += value; show.setText(Double.toString(answer)); field.setText(""); } }); minus.addActionListener(e -> {// minus number = field.getText(); if (!number.equals("")) { double value = Double.parseDouble(number); answer -= value; show.setText(Double.toString(answer)); field.setText(""); } }); Multiply.addActionListener(e -> {// multiply number = field.getText(); if (!number.equals("")) { double value = Double.parseDouble(number); answer *= value; show.setText(Double.toString(answer)); field.setText(""); } }); divide.addActionListener(e -> {// divide number = field.getText(); if (!number.equals("")) { double value = Double.parseDouble(number); answer /= value; show.setText(Double.toString(answer)); field.setText(""); } }); add(button); add(field); add(result); this.setLayout(new GridLayout(3, 1)); this.setVisible(true); }错哪了

这段代码似乎是一个简单的计算器程序，但是在代码中没有定义 `field` 变量，因此在添加 `field` 变量时，需要先进行定义。此外，在 `Multiply` 和 `divide` 的实现中，没有对除数为0的情况进行处理，这会导致程序抛出异常。因此应该在这两个实现中添加对除数为0的情况进行处理的代码。

相关问题

public class Calculator extends JFrame { private JPanel result, button; private JLabel show; private JButton CLR, add, minus, Multiply, divide; private JTextField field; private Double answer; private String number; public Calculator() { super("Calculator"); this.setLocationRelativeTo(null);// set up window this.setResizable(false); this.setDefaultCloseOperation(EXIT_ON_CLOSE); this.setSize(600, 200); result = new JPanel(); answer = 0.0 ; show = new JLabel(Double.toString(answer), SwingConstants.RIGHT);// let the result at the right of the field result.add(show); JTextField filed = new JTextField(Double.toString(answer));// setup the size of the text field filed.setColumns(6); filed.setHorizontalAlignment(JTextField.RIGHT); button = new JPanel(); button.setLayout(new GridLayout(1, 5)); CLR = new JButton("CLR");// add the buttons of calculation. add = new JButton("+"); minus = new JButton("-"); Multiply = new JButton("*"); divide = new JButton("/"); button.add(CLR); button.add(add); button.add(minus); button.add(Multiply); button.add(divide); CLR.addActionListener(e -> {// clear answer = 0.0; show.setText(Double.toString(answer)); field.setText(" "); }); add.addActionListener(e -> {// add number = field.getText(); if (!number.equals(null)) { double value = Double.parseDouble(number); answer += value; show.setText(Double.toString(answer)); field.setText(""); } }); minus.addActionListener(e -> {// minus number = field.getText(); if (!number.equals("")) { double value = Double.parseDouble(number); answer -= value; show.setText(Double.toString(answer)); field.setText(""); } }); Multiply.addActionListener(e -> {// multiply number = field.getText(); if (!number.equals("")) { double value = Double.parseDouble(number); answer *= value; show.setText(Double.toString(answer)); field.setText(""); } }); divide.addActionListener(e -> {// divide number = field.getText(); if (!number.equals("")) { double value = Double.parseDouble(number); answer /= value; show.setText(Double.toString(answer)); field.setText(""); } }); add(button); add(field); add(result); this.setLayout(new GridLayout(3, 1)); this.setVisible(true); }

你好，看起来这是一个实现简单计算器的 Java Swing 程序。程序界面有一个文本框和一些按钮，可以进行加减乘除等基本运算。

程序中的 `JTextField` 组件 `field` 用于输入数字，每当用户点击一个按钮时，程序会读取 `field` 中的数字并进行相应的运算。运算结果会显示在 `JLabel` 组件 `show` 中。

程序中的 `CLR` 按钮可以清除输入的数字并将结果重置为 0。其他按钮则分别对应加、减、乘、除四种运算。当用户点击这些按钮时，程序会从 `field` 中读取数字，并根据当前的运算符进行相应的运算，然后将结果显示在 `show` 中。

这个程序很简单，但可以帮助你了解 Java Swing 程序的基本结构和事件处理机制。如果你想深入了解 Java Swing，可以查看相关的文档或书籍。

3．编写程序实现一个简单计算器的基本功能，具体可以模仿Windows附件中的计算器或模拟常见的实物计算器。使用java

以下是一个简单的基于Java Swing的计算器程序实现：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Calculator extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;
    private JPanel panel;
    private JButton[] buttons;
    private JTextField display;
    private String[] buttonLabels = {"7", "8", "9", "/", "4", "5", "6", "*", "1", "2", "3", "-", "0", ".", "=", "+"};
    private double result = 0;
    private String operator = "";
    private boolean start = true;

    public Calculator() {
        super("Calculator");
        setSize(300, 300);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        setResizable(false);

        panel = new JPanel();
        panel.setLayout(new GridLayout(4, 4));

        buttons = new JButton[buttonLabels.length];
        for (int i = 0; i < buttonLabels.length; i++) {
            buttons[i] = new JButton(buttonLabels[i]);
            buttons[i].addActionListener(this);
            panel.add(buttons[i]);
        }

        display = new JTextField();
        display.setEditable(false);
        display.setHorizontalAlignment(JTextField.RIGHT);

        getContentPane().add(display, BorderLayout.NORTH);
        getContentPane().add(panel, BorderLayout.CENTER);

        setVisible(true);
    }

    public void actionPerformed(ActionEvent event) {
        String command = event.getActionCommand();
        if (command.matches("[0-9\\.]")) {
            if (start) {
                display.setText(command);
                start = false;
            } else {
                display.setText(display.getText() + command);
            }
        } else if (command.matches("[+\\-*/=]")) {
            if (operator.equals("")) {
                result = Double.parseDouble(display.getText());
            } else if (operator.equals("+")) {
                result += Double.parseDouble(display.getText());
            } else if (operator.equals("-")) {
                result -= Double.parseDouble(display.getText());
            } else if (operator.equals("*")) {
                result *= Double.parseDouble(display.getText());
            } else if (operator.equals("/")) {
                result /= Double.parseDouble(display.getText());
            }
            display.setText("" + result);
            operator = command;
            start = true;
        }
    }

    public static void main(String[] args) {
        new Calculator();
    }

}

该程序使用GridLayout布局管理器来排列按钮，并实现了ActionListener接口以处理按钮点击事件。在actionPerformed方法中，程序先判断点击的按钮是数字还是运算符，然后根据不同的运算符来计算结果，并将结果显示在文本框中。