C++引用計數智能指標

標籤：引用計數   智能指標   

#include <iostream>using namespace std;template<typename Type>//引用計數的智能指標class auto_ptr_{public:    auto_ptr_(Type *t = NULL):ptr(t), count(1)    {    }    auto_ptr_(const auto_ptr_<Type>& at) :ptr(at.ptr), count(at.count+1)    {}    auto_ptr_<Type>& operator=(const auto_ptr_<Type> &at)    {        if (this != &at)        {            if (ptr != NULL)            {                if (count == 1)                    this->~auto_ptr_();//如果ptr已經存在且唯一指向目標。                ptr = at.ptr;                count = at.count + 1;            }        }        return *this;    }    ~auto_ptr_()    {        if (count == 1)        {            if (ptr != NULL)            {                delete ptr;                ptr = NULL;            }        }    }    Type* operator->()    {        return ptr;    }    Type& operator*()    {        return *this;    }private:    Type *ptr;    int count;};int main(){    int *a = new int(3);    int *b = new int(4);    auto_ptr_<int> ps(a);    auto_ptr_<int> pb(ps);    auto_ptr_<int> pc(b);    pc=pb;    auto_ptr_<int> pd(pc);    return 0;}

C++引用計數智能指標