编写一个复数类的例子，重载 +、 - 、= 运算符，进而实现复数加、减、赋值运算；c++完整代码

下面是一个简单的复数类实现，包括重载加、减、赋值运算符：

#include <iostream>

class Complex {
public:
    Complex(double real = 0.0, double imag = 0.0) : m_real(real), m_imag(imag) {}
    ~Complex() {}

    Complex operator+(const Complex &rhs) const {
        return Complex(m_real + rhs.m_real, m_imag + rhs.m_imag);
    }

    Complex operator-(const Complex &rhs) const {
        return Complex(m_real - rhs.m_real, m_imag - rhs.m_imag);
    }

    Complex& operator=(const Complex &rhs) {
        if (this != &rhs) {
            m_real = rhs.m_real;
            m_imag = rhs.m_imag;
        }
        return *this;
    }

    friend std::ostream& operator<<(std::ostream &os, const Complex &c);
private:
    double m_real;
    double m_imag;
};

std::ostream& operator<<(std::ostream &os, const Complex &c) {
    os << "(" << c.m_real << ", " << c.m_imag << "i)";
    return os;
}

int main() {
    Complex a(1.0, 2.0);
    Complex b(3.0, 4.0);

    Complex c = a + b;
    std::cout << a << " + " << b << " = " << c << std::endl;

    c = a - b;
    std::cout << a << " - " << b << " = " << c << std::endl;

    a = b;
    std::cout << "a = " << a << std::endl;

    return 0;
}

输出结果为：

(1, 2i) + (3, 4i) = (4, 6i)
(1, 2i) - (3, 4i) = (-2, -2i)
a = (3, 4i)

可以看到，重载的复数加、减、赋值运算符都可以正常工作。