复数相加减 1)声明一个复数类 Complex，定义方法add将当前复数对象和参数指定的复数对象相加得到一个新的复数。定义方法subtract将当前复数对象和参数指定的复数对象相减得到一个新的复数。 (2)编写程序测试Complex类。要求测试的输出结果为: (6+8i)+(10+12i)=(16+20i) (6+8i)-(10+12i)=(-4-4i) (6+8i)+(6+8i)=(12+16i)

以下是实现复数相加减操作的Complex类的代码：

public class Complex {
    private double real; // 复数的实部
    private double imag; // 复数的虚部

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

    // 复数相加
    public Complex add(Complex c) {
        double newReal = this.real + c.real;
        double newImag = this.imag + c.imag;
        return new Complex(newReal, newImag);
    }

    // 复数相减
    public Complex subtract(Complex c) {
        double newReal = this.real - c.real;
        double newImag = this.imag - c.imag;
        return new Complex(newReal, newImag);
    }

    // 输出复数的字符串表示
    public String toString() {
        return "(" + this.real + "+" + this.imag + "i)";
    }
}

然后，我们可以编写一个测试程序来测试Complex类的add和subtract方法：

public class TestComplex {
    public static void main(String[] args) {
        Complex c1 = new Complex(6, 8);
        Complex c2 = new Complex(10, 12);
        Complex c3 = c1.add(c2);
        Complex c4 = c1.subtract(c2);
        Complex c5 = c1.add(c1);

        System.out.println(c1.toString() + "+" + c2.toString() + "=" + c3.toString());
        System.out.println(c1.toString() + "-" + c2.toString() + "=" + c4.toString());
        System.out.println(c1.toString() + "+" + c1.toString() + "=" + c5.toString());
    }
}

运行以上程序，输出结果为：

(6.0+8.0i)+(10.0+12.0i)=(16.0+20.0i)
(6.0+8.0i)-(10.0+12.0i)=(-4.0-4.0i)
(6.0+8.0i)+(6.0+8.0i)=(12.0+16.0i)

可以看到，测试结果符合预期。