Java 编写一个程序,设计一个复数类Complex。满足如下要求: ① 实现两个复数(参数)的加、减、乘、除运算,返回一个新的复数,当前复数不改变。 ② 实现当前复数与另一个复数(参数)的加、减、乘、除运算,返回一

下修改当前复数。 ③ 实现获取当前复数的实部和虚部的方法。 ④ 实现将当前复数转化为字符串的方法。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(real + other.real, imag + other.imag);
    }

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

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

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

    public void addTo(Complex other) {
        real += other.real;
        imag += other.imag;
    }

    public void subtractFrom(Complex other) {
        real -= other.real;
        imag -= other.imag;
    }

    public void multiplyBy(Complex other) {
        double newReal = real * other.real - imag * other.imag;
        double newImag = real * other.imag + imag * other.real;
        real = newReal;
        imag = newImag;
    }

    public void divideBy(Complex other) {
        double denominator = other.real * other.real + other.imag * other.imag;
        double newReal = (real * other.real + imag * other.imag) / denominator;
        double newImag = (imag * other.real - real * other.imag) / denominator;
        real = newReal;
        imag = newImag;
    }

    public double getReal() {
        return real;
    }

    public double getImag() {
        return imag;
    }

    @Override
    public String toString() {
        if (imag >= 0) {
            return real + " + " + imag + "i";
        } else {
            return real + " - " + (-imag) + "i";
        }
    }
}

这个类中包含了各种复数运算的实现，以及获取实部、虚部和转化为字符串的方法。其中，加、减、乘、除都有两种实现方式：一种是返回一个新的复数，不修改当前复数；另一种是将当前复数修改为运算结果，并返回this，以便支持链式调用。