用Java编写复数类的加减乘除运算

复数类（Complex）的代码如下：

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) {
        return new Complex(this.real + other.real, this.imag + other.imag);
    }

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

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

    public Complex divide(Complex other) {
        double denominator = other.real * other.real + other.imag * other.imag;
        double real = (this.real * other.real + this.imag * other.imag) / denominator;
        double imag = (this.imag * other.real - this.real * other.imag) / denominator;
        return new Complex(real, imag);
    }

    public double getReal() {
        return this.real;
    }

    public double getImag() {
        return this.imag;
    }

    public String toString() {
        return this.real + " + " + this.imag + "i";
    }
}

使用示例：

Complex a = new Complex(3, 4);
Complex b = new Complex(1, 2);

Complex c = a.add(b);
System.out.println(c); // 4.0 + 6.0i

Complex d = a.subtract(b);
System.out.println(d); // 2.0 + 2.0i

Complex e = a.multiply(b);
System.out.println(e); // -5.0 + 10.0i

Complex f = a.divide(b);
System.out.println(f); // 2.2 - 0.4i