c++ primer 13.5.1 智能指针

class HasPtr{public:HasPtr(int nVal, int *ptr = NULL):m_nVal(nVal)                      ,m_ptr(ptr){}inline int  GetValue() const { return m_nVal; }inline void SetValue(int &nVal){m_nVal = nVal;}inline int* GetPtr() const {return m_ptr;}inline void SetPtr(int *ptr){m_ptr = ptr;}inline int  GetPtrValue() const {return *m_ptr;}inline void SetPtrValue(int nVal) {*m_ptr = nVal;}private:int          m_nVal;int         *m_ptr;};class HasPtrOther;class U_Ptr{friend class HasPtrOther;U_Ptr(int *p) : m_nUsed(1), m_pn(p){}~U_Ptr(){if(m_pn){delete m_pn;m_pn = NULL;}}int     m_nUsed;     // 使用计数int     *m_pn;};class HasPtrOther{public:HasPtrOther(int nVal, int *ptr) : m_nVal(nVal)                            , m_pU(new U_Ptr(ptr)){}HasPtrOther(const HasPtrOther &rhs): m_nVal(rhs.m_nVal)   , m_pU(rhs.m_pU){++m_pU->m_nUsed;}~HasPtrOther(){if(0 == --m_pU->m_nUsed){delete m_pU;m_pU = NULL;}}HasPtrOther & HasPtrOther::operator=(const HasPtrOther &rhs){++rhs.m_pU->m_nUsed;if(0 == --m_pU->m_nUsed){delete m_pU;m_pU= NULL;}m_nVal = rhs.m_nVal;m_pU   = rhs.m_pU;return *this;}inline int* GetPtr() const {return m_pU->m_pn;}inline void SetPtr(int *ptr){m_pU->m_pn = ptr;}inline int  GetPtrValue() const {return *m_pU->m_pn;}inline void SetPtrValue(int nVal) {*m_pU->m_pn = nVal;}private:int    m_nVal;U_Ptr  *m_pU;};inline void TestPtr(){int *ptr = new int;HasPtr p1(88, ptr);HasPtr p2 = p1;p1.SetPtrValue(20);std::cout << p2.GetPtrValue();RELEASE_MEMORY(ptr);ptr = new int();HasPtrOther ptr1(77, ptr);HasPtrOther ptr2 = ptr1;//HasPtrOther ptr3(66, new int(55));//ptr3 = ptr2;vector<HasPtrOther> vtr;vtr.push_back(ptr1);}