编写复数运算的javaApplication程序： (1)设计复数类Complex，具有实部、虚部两个属性，能完成复数的加、减、乘三种运算。 (2)使用Application创建一图形用户界面程序，界面如下，程序运行时，用户可在“复数1”后面的对应文本框中输入第一个复数的实部和虚部，在“复 数2”后面的对应文本框中输入第二个复数的实部和虚部，在“运算符”后面的文本框中输入“+”或“-”或“*”运算符号，当用户按下“=”按钮后，程序调用复数类Complex的对应方法，将运算结果(计算得到的复数的实部和虚部)显示在其后排列的两个文本框中。

以下是复数类Complex的代码：

public class Complex {
    private double real;
    private double imag;

    public Complex(double real, double imag) {
        this.real = real;
        this.imag = imag;
    }

    public Complex add(Complex other) {
        double realResult = this.real + other.real;
        double imagResult = this.imag + other.imag;
        return new Complex(realResult, imagResult);
    }

    public Complex subtract(Complex other) {
        double realResult = this.real - other.real;
        double imagResult = this.imag - other.imag;
        return new Complex(realResult, imagResult);
    }

    public Complex multiply(Complex other) {
        double realResult = this.real * other.real - this.imag * other.imag;
        double imagResult = this.real * other.imag + this.imag * other.real;
        return new Complex(realResult, imagResult);
    }

    public String toString() {
        String sign = this.imag >= 0 ? "+" : "-";
        return this.real + sign + Math.abs(this.imag) + "i";
    }
}

以下是图形用户界面程序的代码：

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

public class ComplexCalculator extends JFrame {
    private JTextField realField1;
    private JTextField imagField1;
    private JTextField realField2;
    private JTextField imagField2;
    private JTextField operatorField;
    private JTextField realResultField;
    private JTextField imagResultField;

    public ComplexCalculator() {
        // Create labels
        JLabel complex1Label = new JLabel("复数1:");
        JLabel complex2Label = new JLabel("复数2:");
        JLabel operatorLabel = new JLabel("运算符:");
        JLabel equalsLabel = new JLabel("=");
        JLabel resultLabel = new JLabel("计算结果:");

        // Create text fields
        realField1 = new JTextField(5);
        imagField1 = new JTextField(5);
        realField2 = new JTextField(5);
        imagField2 = new JTextField(5);
        operatorField = new JTextField(2);
        realResultField = new JTextField(5);
        imagResultField = new JTextField(5);
        realResultField.setEditable(false);
        imagResultField.setEditable(false);

        // Create button
        JButton calculateButton = new JButton("计算");
        calculateButton.addActionListener(new CalculateButtonListener());

        // Create panel for input fields
        JPanel inputPanel = new JPanel(new GridLayout(2, 3));
        inputPanel.add(complex1Label);
        inputPanel.add(realField1);
        inputPanel.add(new JLabel("+"));
        inputPanel.add(imagField1);
        inputPanel.add(complex2Label);
        inputPanel.add(realField2);
        inputPanel.add(new JLabel("+"));
        inputPanel.add(imagField2);

        // Create panel for operator field and button
        JPanel operatorPanel = new JPanel();
        operatorPanel.add(operatorLabel);
        operatorPanel.add(operatorField);
        operatorPanel.add(calculateButton);

        // Create panel for result fields
        JPanel resultPanel = new JPanel(new GridLayout(2, 3));
        resultPanel.add(resultLabel);
        resultPanel.add(realResultField);
        resultPanel.add(new JLabel("+"));
        resultPanel.add(imagResultField);
        resultPanel.add(equalsLabel);
        resultPanel.add(new JLabel(""));

        // Create main panel and add components
        JPanel mainPanel = new JPanel(new BorderLayout());
        mainPanel.add(inputPanel, BorderLayout.NORTH);
        mainPanel.add(operatorPanel, BorderLayout.CENTER);
        mainPanel.add(resultPanel, BorderLayout.SOUTH);

        // Add main panel to frame
        this.setContentPane(mainPanel);
        this.pack();
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
    }

    private class CalculateButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            // Get input values
            double real1 = Double.parseDouble(realField1.getText());
            double imag1 = Double.parseDouble(imagField1.getText());
            double real2 = Double.parseDouble(realField2.getText());
            double imag2 = Double.parseDouble(imagField2.getText());
            String operator = operatorField.getText();

            // Perform calculation
            Complex complex1 = new Complex(real1, imag1);
            Complex complex2 = new Complex(real2, imag2);
            Complex result = null;
            switch (operator) {
                case "+":
                    result = complex1.add(complex2);
                    break;
                case "-":
                    result = complex1.subtract(complex2);
                    break;
                case "*":
                    result = complex1.multiply(complex2);
                    break;
            }

            // Display result
            if (result != null) {
                realResultField.setText(Double.toString(result.getReal()));
                imagResultField.setText(Double.toString(result.getImag()));
            }
        }
    }

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

运行该程序，即可在界面上输入两个复数和运算符，然后按下“计算”按钮，即可显示计算结果。