智能指標一個簡單例子

/** The Code Project Open License (CPOL) 1.02**/class RC{private:    int count; // Reference countpublic:    void AddRef()    {        // Increment the reference count        count++;    }    int Release()    {        // Decrement the reference count and        // return the reference count.        return --count;    }};template < typename T > class SP{private:    T*    pData;       // pointer    RC* reference; // Reference countpublic:    SP() : pData(0), reference(0)     {        // Create a new reference         reference = new RC();        // Increment the reference count        reference->AddRef();    }    SP(T* pValue) : pData(pValue), reference(0)    {        // Create a new reference         reference = new RC();        // Increment the reference count        reference->AddRef();    }    SP(const SP<T>& sp) : pData(sp.pData), reference(sp.reference)    {        // Copy constructor        // Copy the data and reference pointer        // and increment the reference count        reference->AddRef();    }    ~SP()    {        // Destructor        // Decrement the reference count        // if reference become zero delete the data        if(reference->Release() == 0)        {            delete pData;            delete reference;        }    }    T& operator* ()    {        return *pData;    }    T* operator-> ()    {        return pData;    }        SP<T>& operator = (const SP<T>& sp)    {        // Assignment operator        if (this != &sp) // Avoid self assignment        {            // Decrement the old reference count            // if reference become zero delete the old data            if(reference->Release() == 0)            {                delete pData;                delete reference;            }            // Copy the data and reference pointer            // and increment the reference count            pData = sp.pData;            reference = sp.reference;            reference->AddRef();        }        return *this;    }};

使用例子：