#include <iostream>
#include <stdio.h>
#include <stdlib.h>

using namespace std;

class Operat
{
    float x;
    float y;
public:
    Operat(float _x = 0,float _y = 0)    
    {
        x = _x;
        y = _y;
    }
    Operat(Operat& that)
    {
        x = that.x;
        y = that.y;
    }
    
 
/*
    Operat operator + (Operat& that) //成員函數+重載
    {
        Operat t;
        t.x = x + that.x;
        t.y = y + that.y;
        return t;
    }
    Operat& operator ++ (void)//成員函數前++重載
    {
        x++;
        y++;
        return *this;
    }
    Operat operator ++ (int)//成員函數後++重載
    {
        Operat t(*this);
        t.x++;
        t.y++;
        return t;
    }
 
*/
    Operat& operator [] (int i)//成員函數[]重載
    {
        return *(this+i);
    }
    Operat& operator -> (void)//成員函數->重載
    {
        return *this;
    }
　

　　　　void show()
　　　　{
　　　　　　printf("x=%f,y=%f\n",x,y);
　　　　}

　　　　//註意：普通函數 在類裏加上friend聲明成類的友元以後 就可以使用類的成員變量，不然成員變量一般式封裝在類裏的。外面函數是無法使用的

    friend Operat operator + (Operat& a,Operat& b); //聲明友員函數 ，這樣外部函數就可以訪問類的成員變量 
    friend Operat& operator ++ (Operat& a);
    friend Operat operator ++ (Operat& a,int);
    friend ostream& operator << (ostream& os,Operat& p);
    friend istream& operator >> (istream& is,Operat& p);
    ~Operat(){}
};

void* operator new (unsigned int size)//全局函數new的重載
{
        return malloc(size);
}

Operat operator + (Operat& a,Operat& b)//全局函數+的重載
{
    Operat t(a.x+b.x,a.y+b.y);
    return t;
}

Operat& operator ++ (Operat& a)//全局函數前++的重載
{
    a.x++;
    a.y++;
    return a;
}

Operat operator ++ (Operat& a,int)//全局函數後++的重載
{
    Operat t = a;
    a.x++;
    a.y++;
    return t;
}

ostream& operator << (ostream& os,Operat& p)//全局函數 << 的重載
{
    return os << "x=" << p.x << " " << "y=" << p.y << " ";
}

istream& operator >> (istream& is,Operat& p)//全局函數 >> 的重載
{
    return is >> p.x >> p.y;
}

int main()
{
    Operat a(1,2);
    Operat b(3,4);
    (a++).show();
    a.show();
    cin >> a;
    cout << a << b << endl;
}

C++中特殊運算符的重載