使用成员函数重载复数类的运算符+

以下是复数类的成员函数重载运算符的示例：

class Complex {
  private:
    double real;
    double imag;

  public:
    Complex(double r = 0, double i = 0) : real(r), imag(i) {}

    Complex operator+(const Complex& c) const {
        return Complex(real + c.real, imag + c.imag);
    }

    Complex operator-(const Complex& c) const {
        return Complex(real - c.real, imag - c.imag);
    }

    Complex operator*(const Complex& c) const {
        return Complex(real * c.real - imag * c.imag, real * c.imag + imag * c.real);
    }

    Complex operator/(const Complex& c) const {
        double r = c.real * c.real + c.imag * c.imag;
        return Complex((real * c.real + imag * c.imag) / r, (imag * c.real - real * c.imag) / r);
    }

    Complex operator+=(const Complex& c) {
        real += c.real;
        imag += c.imag;
        return *this;
    }

    Complex operator-=(const Complex& c) {
        real -= c.real;
        imag -= c.imag;
        return *this;
    }

    Complex operator*=(const Complex& c) {
        double r = real * c.real - imag * c.imag;
        double i = real * c.imag + imag * c.real;
        real = r;
        imag = i;
        return *this;
    }

    Complex operator/=(const Complex& c) {
        double r = c.real * c.real + c.imag * c.imag;
        double nreal = (real * c.real + imag * c.imag) / r;
        double nimag = (imag * c.real - real * c.imag) / r;
        real = nreal;
        imag = nimag;
        return *this;
    }

    bool operator==(const Complex& c) const {
        return real == c.real && imag == c.imag;
    }

    bool operator!=(const Complex& c) const {
        return !(*this == c);
    }
};

这个示例中，复数类有四个基本的运算符：加、减、乘、除。每个运算符都返回一个新的复数对象，而不是修改当前对象。此外，还有四个复合赋值运算符（+=、-=、*=、/=），它们修改当前对象并返回它。最后，还有两个比较运算符（== 和 !=），它们比较两个复数对象的实部和虚部是否相等。