1. 定义复数(Complex)类 。 要求: (1)复数有实部和虚部属性; (2)定义类的构造方法; (3)实现复数加减法并输出复数属性的值。 (4)重载toString方法，用于对象属性值的输出。

好的，以下是一个简单的复数类的实现：

#include <iostream>
using namespace std;

class Complex {
private:
    double real; // 实部
    double imag; // 虚部

public:
    Complex(double real, double imag) {
        this->real = real;
        this->imag = imag;
    }

    // 复数加法
    Complex add(Complex other) {
        double newReal = this->real + other.real;
        double newImag = this->imag + other.imag;
        return Complex(newReal, newImag);
    }

    // 复数减法
    Complex subtract(Complex other) {
        double newReal = this->real - other.real;
        double newImag = this->imag - other.imag;
        return Complex(newReal, newImag);
    }

    // 重载 toString 方法
    friend ostream& operator<<(ostream& os, const Complex& c) {
        os << c.real << " + " << c.imag << "i";
        return os;
    }
};

这个类有一个构造方法，用于初始化实部和虚部。它还有两个方法，用于实现复数的加减法。最后，它重载了 << 运算符，用于输出对象属性值。你可以通过下面的代码来测试这个类：

int main() {
    Complex c1(1, 2);
    Complex c2(3, 4);

    Complex sum = c1.add(c2);
    Complex diff = c1.subtract(c2);

    cout << "c1 = " << c1 << endl;
    cout << "c2 = " << c2 << endl;
    cout << "sum = " << sum << endl;
    cout << "diff = " << diff << endl;

    return 0;
}

输出结果应该是：

c1 = 1 + 2i
c2 = 3 + 4i
sum = 4 + 6i
diff = -2 - 2i