C++primer读书笔记8重载操作符

Item item1 ,item2;
item1 + item2;		// call method 1
operator+(item1,item2)	// call method 2
// if + is operator of class
item1 + item2;
item1.operator+(item2);

2 重载操作符的谨记

// output.h
#pragma once
#include <iostream>
using namespace std;
class Input
{
public:
Input(void);
~Input(void);
ostream& operator <<(ostream& out);
private:
string str;
int fun;
};


// output.cpp
#include "Input.h"
Input::Input(void)
{
str = "keep move on";
fun = 1001;
}
Input::~Input(void)
{
}
ostream& Input::operator<<(ostream& out)
{
out<<"persist on"<<fun<<endl;
return out;
}


//main.cpp
#include "Input.h"
void main()
{
Input in;
in<<cout<<"I'll always find you"<<endl;
}

#pragma once
#include <vector>
using namespace std;
class XB
{
public:
XB(void);
~XB(void);
int& operator [](const size_t index);
const int& operator [](const size_t index)const;
private:
vector<int> data;
};


//XB.cpp
#include "XB.h"
XB::XB(void)
{
data = vector<int>(5,2);
}


XB::~XB(void)
{
}


int& XB::operator [](const size_t index)
{
return data[index];
}


const int& XB::operator[](const size_t index)const
{
return data[index];
}


//main.cpp
#include "XB.h"
#include <iostream>
using namespace std;
void main()
{
XB xb;
cout<<xb[3];
xb[1] = 10;
cout<<xb[1];
system("pause");
}

#include <iostream>
using namespace std;
class Tv
{
public:
Tv(void):m_height(100),m_width(390){};
~Tv(void){};
int func(){return m_height * m_width;}
private:
int m_height;
int m_width;
};


class TvPtr
{
friend class TvPtrCnt;
Tv* sp;
size_t use;
TvPtr(Tv* p):sp(p),use(1){}
~TvPtr(){delete sp;}
};


class TvPtrCnt
{
public:
TvPtrCnt(Tv* p):ptr(new TvPtr(p)){}
TvPtrCnt(const TvPtrCnt& orig):ptr(orig.ptr){++ptr->use;};
TvPtrCnt& operator =(const TvPtrCnt &orig){++ptr->use;}
~TvPtrCnt(){if(--ptr->use ==0) delete ptr;}


Tv& operator*(){return *ptr->sp;}
Tv* operator->(){return ptr->sp;}
const Tv& operator*()const{return *ptr->sp;}
const Tv* operator->()const{return ptr->sp;}
private:
TvPtr* ptr;
};
void main()
{
Tv *p = new Tv();
TvPtrCnt zp(p);
std::cout<<(*zp).func()<<std::endl;
std::cout<<zp->func()<<std::endl;

system("pause");
}

XXX& operator++();
XXX& operator--();

XXX operator++(int);
XXX operator--(int);

XXX.operator++(); //prefix
XXX.operator++(0); //postfix

12 调用操作符和函数对象

#include <iostream>
using namespace std;
class Abs
{
public:
Abs(){}
~Abs(){}
int operator ()(int val){return val <0 ? -val : val;}
};
void main()
{
Abs XX;
cout<<XX(-108)<<endl;
system("pause");
}

C++primer读书笔记8重载操作符

原文：http://blog.csdn.net/ddupd/article/details/38001567