智能指针的一种实现

std的auto_ptr实现了接口

T* get() 返回原始指针

void reset() 析构原始指针指向的对象

T* operator ->() 返回原始指针

T& operator *() 返回原始指针指向的对象的引用

T* release() 交还原始指针管理权

基于以上功能要求，实现智能指针如下

#pragma once

template<class T>
class smart_ptr{
public:
//smart_ptr():m_p(0){}
smart_ptr(T *p):m_p(p){}
~smart_ptr();
T* get() {return m_p;}
void reset();
T* release();
T* operator -> () {return m_p;}
T& operator *() {return *m_p;}
private:

smart_ptr(smart_ptr &);   // declare copy constructor and operator = as private to avoid misuse smart_ptr
smart_ptr& operator =(smart_ptr&);//
T *m_p;
};

template<class T>
T* smart_ptr<T>::release()
{
T* temp = m_p;
m_p = 0;
return temp;
}

template<class T>
void smart_ptr<T>::reset()
{
if (m_p)
{
delete m_p;
m_p = 0;
}
}

template<class T>
smart_ptr<T>::~smart_ptr()
{
reset();
}

测试类

class testClass
{
public:
testClass(){cout<<"construction testClass"<<endl;}
~testClass(){cout<<"destruction testClass"<<endl;}
void print(){cout<<m_str<<endl;}
string m_str;
};

测试代码

#include <stdio.h>
#include <tchar.h>
#include <string>
#include <ctime>
#include <map>
#include <iostream>
#include <algorithm>
#include "header.hpp"
using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
smart_ptr<testClass> sp1(new testClass);

sp1.get()->m_str = "111";
sp1->print();
(*sp1).m_str = "2222";
sp1->print();

//smart_ptr<testClass> sp2 = sp1;//compile error since copy constructor is declared as private

testClass *p = sp1.release();
delete p;
return 0;
}