定义复数的类Complex并测试其功能： 1. 复数由实部、虚部两个部分组成，在类的定义中应包含保存这两部分信息的内容。 2. 在类中定义构造函数，使用户能够在构造对象的同时为对象赋初值。 3. 在类中定义复数的加法、减法、乘法三个成员方法来完成复数间的加、减、乘的功能。 4. 通过重载toString方法，使得Complex类的对象能够显示其自身信息。

好的，我理解了你的要求。以下是实现上述功能的Complex类的代码示例：

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 newReal = this.real + other.real;
        double newImag = this.imag + other.imag;
        return new Complex(newReal, newImag);
    }

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

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

    @Override
    public String toString() {
        return real + " + " + imag + "i";
    }
}

使用示例：

public static void main(String[] args) {
    Complex c1 = new Complex(1, 2);
    Complex c2 = new Complex(3, 4);

    System.out.println("c1 = " + c1);
    System.out.println("c2 = " + c2);
    System.out.println("c1 + c2 = " + c1.add(c2));
    System.out.println("c1 - c2 = " + c1.subtract(c2));
    System.out.println("c1 * c2 = " + c1.multiply(c2));
}

输出结果：

c1 = 1.0 + 2.0i
c2 = 3.0 + 4.0i
c1 + c2 = 4.0 + 6.0i
c1 - c2 = -2.0 - 2.0i
c1 * c2 = -5.0 + 10.0i

希望这个示例可以帮助你理解如何实现Complex类。