c++ -> 运算符重载（+ && -）

#include <iostream>

using namespace std;

class Complex
{
private:
    int a;
    int b;
    friend Complex myAdd(Complex &c1, Complex &c2);
    friend Complex operator+(Complex &c1, Complex &c2);
    friend Complex myMinus(Complex &c1, Complex &c2);
    friend Complex operator-(Complex &c1, Complex &c2);
public:
    Complex(int a = 0, int b = 0)
    {
        this->a = a;
        this->b = b;
    }
    void printCom()
    {
        cout << a << "+" << b << "i" << endl;
    }
};

//定义全局函数
Complex myAdd(Complex &c1, Complex &c2)
{
    Complex tmp(c1.a + c2.a, c1.b + c2.b);
    return tmp;
}

Complex operator+(Complex &c1, Complex &c2)
{
    Complex tmp(c1.a + c2.a, c1.b + c2.b);
    return tmp;
}

//实现减法的运算符重载
Complex myMinus(Complex &c1, Complex &c2)
{
    Complex tmp(c1.a - c2.a, c1.b - c2.b);
    return tmp;
}

Complex operator-(Complex &c1, Complex &c2)
{
    Complex tmp(c1.a - c2.a, c1.b - c2.b);
    return tmp;
}

// + 号测试函数
int main01()
{
    Complex c1(1, 2), c2(3, 4);

    //方法1
    Complex c4 = myAdd(c1, c2);
    c4.printCom();

    //方法2
    Complex c3 = operator+(c1, c2);
    c3.printCom();

    //方法3
    Complex c5 = c1 + c2;
    c5.printCom();


    return 0;
}

// - 号测试函数
int main()
{
    Complex c1(1, 2), c2(3, 4);

    //方法1
    Complex c4 = myMinus(c1, c2);
    c4.printCom();

    //方法2
    Complex c3 = operator-(c1, c2);
    c3.printCom();

    //方法3
    Complex c5 = c1 - c2;
    c5.printCom();


    return 0;
}