智能指针实现

问题描述

我的尝试（下方）在实施

类似智能指针的东西时有什么问题吗？


模板< T级>

级SmartPointer

{

私人：

T * t;


public：

SmartPointer（）{t = new T（）;}

SmartPointer（const SmartPointer< T>& rhs）{t = rhs.t;}

T& operator *（）const {return（* t）;}

T * operator->（）const {return（t）;}

SmartPointer< T>& ; operator =（const SmartPointer< T>& rhs）{t = rhs.t;返回（* this）;}

~SmartPointer（）{删除t;}

};


我写的程序为了测试这次崩溃，我根本不会这么做，因为我知道我在某处犯了错误。不，我不能使用Boost来实现这一点。


-

Christopher Benson-Manica |我*应该*知道我在说什么 - 如果我

ataru（at）cyberspace.org |不，我需要知道。火焰欢迎。

Is there anything wrong with my attempt (below) at implementing
something resembling a smart pointer?

template < class T >
class SmartPointer
{
private:
T *t;

public:
SmartPointer() {t=new T();}
SmartPointer( const SmartPointer<T> &rhs ) {t=rhs.t;}
T& operator*() const {return(*t);}
T* operator->() const {return(t);}
SmartPointer<T>& operator= ( const SmartPointer<T> &rhs ) {t=rhs.t; return(*this);}
~SmartPointer() {delete t;}
};

The program I wrote to test this crashes, and I wouldn''t be at all
surprised to learn that I''ve made a mistake here somewhere. And no, I
can''t use Boost for this.

--
Christopher Benson-Manica | I *should* know what I''m talking about - if I
ataru(at)cyberspace.org | don''t, I need to know. Flames welcome.

推荐答案

是的。你复制构造函数是错误的。它会成员复制，当它需要做一个深层复制时。


SmartPointer（const SmartPointer< T>& rhs）{t = new T （rhs.t）; }


适用于您的任务操作员


-

Karl Heinz Buchegger

是的。你复制构造函数是错误的。当它应该进行深层复制时，它会进行成员复制。

SmartPointer（const SmartPointer< T>& rhs）{t = new T（rhs.t）; }

你的任务操作员也一样

Yep. You copy constructor is wrong. It does a memberwise copy, when
it should do a deep copy.

SmartPointer( const SmartPointer<T> &rhs ) {t = new T( rhs.t ); }

same for your assignment operator

实际上，任务操作员的情况更糟。

因为它现在，它还会泄漏内存


-

Karl Heinz Buchegger

删除t;在任务之前，当然:)谢谢！


-

Christopher Benson-Manica |我*应该*知道我在说什么 - 如果我

ataru（at）cyberspace.org |不，我需要知道。火焰欢迎。

With delete t; coming before the assignment, of course :) Thanks!

--
Christopher Benson-Manica | I *should* know what I''m talking about - if I
ataru(at)cyberspace.org | don''t, I need to know. Flames welcome.

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