C++ 单目运算 and 双目运算符重载complex

1 单目运算

#include<iostream>
using namespace std;
//复数
class Complex{
    public:
    double real,image;
    Complex()=default;
    Complex(double r, double i)
    :real(r),image(i){}
    ~Complex(){}
    Complex operator++(int i)
    {
        Complex tmp;
        tmp.real = this->real++;
        tmp.image = this->image++;
        return tmp;
    }
    Complex operator++()
    {
        this->real++;
        this->image++;
        return *this;
    }
};

int main()
{
    Complex c1(10,20);
    Complex c2;
//  c2 = c1++;
    c2 = ++c1;
    cout<<c1.real<<endl;
    cout<<c1.image<<endl;
    cout<<c2.real<<endl;
    cout<<c2.image<<endl;
    return 0;
}

2 双目运算符重载complex.cpp

#include<iostream>
using namespace std;
//复数
class Complex{
    public:
    double real,image;
    Complex()=default;
    Complex(double r, double i)
    :real(r),image(i){}
    ~Complex(){}
    Complex add(Complex c)
    {
        Complex tmp;
        tmp.real = this->real+ c.real;
        tmp.image= this->image+c.image;
        return tmp;
    }
    Complex operator+(Complex c)
    {
        Complex tmp;
        tmp.real = this->real+ c.real;
        tmp.image= this->image+c.image;
        return tmp;
    }
friend Complex operator-(Complex c1,Complex c2);
};
Complex operator-(Complex c1,Complex c2)
{
        Complex tmp;
        tmp.real = c1.real - c2.real;
        tmp.image= c1.image-c2.image;
        return tmp;
}

int main()
{
    Complex c1(10,20);
    Complex c2(10,20);
    Complex c3 ;
    c3 = c1+c2;
//  c3 = c1.add(c2);
    cout<<c3.real<<endl;
    cout<<c3.image<<endl;

    c1 = c3 - c3;
    cout<<c1.real<<endl;
    cout<<c1.image<<endl;
    return 0;
}