智能指针

来源：互联网发布：trpg跑团软件编辑：程序博客网时间：2024/05/01 06:45

1、auto_ptr的简单实现

auto_ptr的性质：会转让所有权（当拷贝构造或者复制赋值发生时）

template<class T>class auto_ptr {private:T *m_ptr;T * release() {T *value = m_ptr;m_ptr = 0;return value;}public:auto_ptr<T>(T *_p=0): m_ptr(_p) {}auto_ptr<T>(const auto_ptr<T> &copy) :m_ptr(copy.release()) {}auto_ptr<T>& operator=(const auto_ptr<T> &assign) {if (this != &assign) {delete m_ptr;                                m_ptr = assign.release();}return *this;}T& operator *() { return *m_ptr; }T * operator ->() {return m_ptr; }~auto_ptr<T>() { delete m_ptr; }};

2、带有引用计数的智能指针的实现

template<typename T>class countedPtr {private:T *m_ptr;long *count;void dispose() {if (-- *count == 0) {delete count;delete m_ptr;}}public:explicit countedPtr<T>(T *_p): m_ptr(_p), count(new long(1)) {}countedPtr<T>(const countedPtr<T> &copy): m_ptr(copy.m_ptr), count(copy.count) {++ *count;}countedPtr<T>& operator=(const countedPtr<T> & assign) {if (this != &assign) {dispose();m_ptr = assign.m_ptr;count = assign.count;++ *count;}return *this;}T & operator *() { return *m_ptr; }T * operator->() { return m_ptr; }~countedPtr() { dispose(); }};

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