定义一个复数类complex，建立一个Complex对象并调用

在面向对象编程中，定义一个复数类（Complex）通常需要包含复数的实部（real part）和虚部（imaginary part），以及对复数进行操作的方法，例如加法、减法、乘法、除法等。以下是一个简单的复数类的定义以及如何创建一个Complex对象并进行基本操作的示例：

public class Complex {
    private double real;   // 实部
    private double imaginary; // 虚部

    // 构造函数
    public Complex(double real, double imaginary) {
        this.real = real;
        this.imaginary = imaginary;
    }

    // 获取实部
    public double getReal() {
        return real;
    }

    // 设置实部
    public void setReal(double real) {
        this.real = real;
    }

    // 获取虚部
    public double getImaginary() {
        return imaginary;
    }

    // 设置虚部
    public void setImaginary(double imaginary) {
        this.imaginary = imaginary;
    }

    // 加法操作
    public Complex add(Complex other) {
        return new Complex(this.real + other.real, this.imaginary + other.imaginary);
    }

    // 减法操作
    public Complex subtract(Complex other) {
        return new Complex(this.real - other.real, this.imaginary - other.imaginary);
    }

    // 乘法操作
    public Complex multiply(Complex other) {
        double newReal = this.real * other.real - this.imaginary * other.imaginary;
        double newImaginary = this.real * other.imaginary + this.imaginary * other.real;
        return new Complex(newReal, newImaginary);
    }

    // 除法操作
    public Complex divide(Complex other) {
        double denominator = other.real * other.real + other.imaginary * other.imaginary;
        double newReal = (this.real * other.real + this.imaginary * other.imaginary) / denominator;
        double newImaginary = (this.imaginary * other.real - this.real * other.imaginary) / denominator;
        return new Complex(newReal, newImaginary);
    }

    // 字符串表示
    @Override
    public String toString() {
        return "(" + real + " + " + imaginary + "i)";
    }
}

// 使用Complex类
public class ComplexTest {
    public static void main(String[] args) {
        Complex c1 = new Complex(3.0, 4.0); // 创建Complex对象c1
        Complex c2 = new Complex(1.0, -2.0); // 创建Complex对象c2

        // 调用复数对象的方法
        Complex sum = c1.add(c2); // c1加c2
        Complex difference = c1.subtract(c2); // c1减c2
        Complex product = c1.multiply(c2); // c1乘c2
        Complex quotient = c1.divide(c2); // c1除c2

        // 打印结果
        System.out.println("Sum: " + sum);
        System.out.println("Difference: " + difference);
        System.out.println("Product: " + product);
        System.out.println("Quotient: " + quotient);
    }
}

在这个例子中，我们定义了一个复数类`Complex`，它有两个属性`real`和`imaginary`，以及几个基本操作的方法。然后在`ComplexTest`类的`main`方法中，我们创建了两个`Complex`对象，并对它们执行了加、减、乘、除运算，最后将结果打印到控制台。