实验要求编写一个应用程序有一个标题为计算的窗口窗口的布局为FlowLayout布局。设计四个按钮分别命名为加、差、积、、除；另外窗口中还有三个文本框。单击相应的按钮将两个文本框的数字做运算在第三个文本框中显示结果。代码

如下：

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

public class Calculator extends JFrame implements ActionListener { private JButton addButton, subButton, mulButton, divButton; private JTextField inputField1, inputField2, resultField;

public Calculator() {
    setTitle("计算");
    setLayout(new FlowLayout());

    addButton = new JButton("加");
    subButton = new JButton("差");
    mulButton = new JButton("积");
    divButton = new JButton("除");

    inputField1 = new JTextField(10);
    inputField2 = new JTextField(10);
    resultField = new JTextField(10);
    resultField.setEditable(false);

    add(new JLabel("数字1："));
    add(inputField1);
    add(new JLabel("数字2："));
    add(inputField2);
    add(new JLabel("结果："));
    add(resultField);
    add(addButton);
    add(subButton);
    add(mulButton);
    add(divButton);

    addButton.addActionListener(this);
    subButton.addActionListener(this);
    mulButton.addActionListener(this);
    divButton.addActionListener(this);

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    pack();
    setLocationRelativeTo(null);
    setVisible(true);
}

public void actionPerformed(ActionEvent e) {
    int num1 = Integer.parseInt(inputField1.getText());
    int num2 = Integer.parseInt(inputField2.getText());

    if (e.getSource() == addButton) {
        resultField.setText("" + (num1 + num2));
    } else if (e.getSource() == subButton) {
        resultField.setText("" + (num1 - num2));
    } else if (e.getSource() == mulButton) {
        resultField.setText("" + (num1 * num2));
    } else if (e.getSource() == divButton) {
        if (num2 == 0) {
            resultField.setText("除数不能为0");
        } else {
            resultField.setText("" + (num1 / num2));
        }
    }
}

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