int main()
{
  int *p = new int;  //裸指针
  delete p;
  return 0;
}

int main()
{
  int *p1 = new int(2);
  int *p2 = p1;
  int *p3 = p2;
  cout<<*p1<<endl;
  cout<<*p2<<endl;
  cout<<*p3<<endl;
  delete p1;
  cout<<*p2<<endl;
  return 0;
}

2
2
2
-572662307

class Test
{
public:
  Test()
  {
    cout<<"Test()"<<endl;
  }
  ~Test()
  {
    cout<<"~Test()"<<endl;
  }
  void func()
  {
    cout<<"call Test::func()"<<endl;
  }
};
template<typename T>
class CSmartptr
{
public:
  CSmartptr(T *ptr):_ptr(ptr)
  {cout<<"CSmartptr()"<<endl;}
  CSmartptr(const CSmartptr<T> &other)
  {
    _ptr = new T;
    *ptr = *other._ptr;
  }
  ~CSmartptr()
  {
    cout<<"~CSmartptr()"<<endl;
    delete _ptr;
  }
  void relase() const
  {
    ((CSmartptr<T> *)this)->owns = false;
  }
  T& operator*()
  {
    return *_ptr;
  }
  const T& operator*()const {return *_ptr;}
  T *operator->()
  {
    return _ptr;
  }
  const T *operator->()const {return _ptr;}
private:
  T *_ptr;
};
int main()
{
  CSmartptr<int> p1(new int);
  *p1 = 200;
  CSmartptr<Test> p2(new Test);
  p2->func();
  return 0;
}

template<typename T>
class CSmartptr
{
public:
  CSmartptr(T *ptr):_ptr(ptr),owns(true){cout<<"CSmartptr()"<<endl;}
  CSmartptr(const CSmartptr<T> &other)
  {
    other.relase();
    _ptr = other._ptr;
  }
  ~CSmartptr()
  {
    cout<<"~CSmartptr()"<<endl;
    if( owns == true)
    {
      cout<<"~CSmartptr()"<<endl;
      delete _ptr;
    }

  }
  void relase() const
  {
    ((CSmartptr<T> *)this)->owns = false;
  }
  T& operator*()
  {
    return *_ptr;
  }
  const T& operator*()const {return *_ptr;}
  T *operator->()
  {
    return _ptr;
  }
  const T *operator->()const {return _ptr;}
private:
  T *_ptr;
  bool owns; //标志位 ,控制一个资源的访问权限
};
int main()
{
  CSmartptr<int> p1(new int);
  *p1 = 200;
  CSmartptr<Test> p2(new Test);
  p2->func();
  return 0;
}

class CHeapTable
{
public:
  static CHeapTable& getInstance()
  {
    return mHeapTable;
  }
  //增加引用计数
  void addRef(void *ptr)
  {
    pthread_mutex_lock(mutex);
    list<Node>::iterator it = find(mList.begin(),
      mList.end(), ptr); // Node == Node it->mpaddr
    if(it == mList.end())
    {
      mList.push_front(ptr);
      cout<<"new addr:"<<ptr<<" ref:"<<1<<endl;
    }
    else
    {
      it->mcount++;
      cout<<"add addr:"<<ptr<<" ref:"<<it->mcount<<endl;
    }
    pthread_mutex_unlock(mutex);
  }
  //减少引用计数的
  void delRef(void *ptr)
  {
    list<Node>::iterator it = find(mList.begin(),
      mList.end(), ptr);
    if(it != mList.end())
    {
      it->mcount--;
      cout<<"del addr:"<<ptr<<" ref:"<<it->mcount<<endl;
      if(it->mcount == 0)
      {
        mList.erase(it);
      }
    }
  }
  //获取引用计数的
  int getRef(void *ptr)
  {
    list<Node>::iterator it = find(mList.begin(),
      mList.end(), ptr);
    if(it != mList.end())
    {
      return it->mcount;
    }
    return 0;
  }
private:
  CHeapTable(){}
  static CHeapTable mHeapTable;

  struct Node
  {
    Node(void *ptr=NULL):mpaddr(ptr),mcount(1){}
    bool operator==(const Node &src)
    {
      return mpaddr == src.mpaddr;
    }
    void *mpaddr; //标识堆内存资源
    int mcount; //标识资源的引用计数
  };

  list<Node> mList;
};
CHeapTable CHeapTable::mHeapTable;
template<typename T>
class CSmartPtr
{
public:
  CSmartPtr(T *ptr = NULL)
    :mptr(ptr)
  {
    if(mptr != NULL)
    {
      addRef();
    }
  }
  ~CSmartPtr()
  {
    delRef();
    if(0 == getRef())
    {
      delete mptr; 
      mptr = NULL;
    }
  }

  CSmartPtr(const CSmartPtr<T> &src)
    :mptr(src.mptr)
  {
    if(mptr != NULL)
    {
      addRef();
    }
  }

  CSmartPtr<T>& operator=(const CSmartPtr<T> &src)
  {
    if(this == &src)
      return *this;

    delRef();
    if(0 == getRef())
    {
      delete mptr;
      mptr = NULL;
    }

    mptr = src.mptr;
    if(mptr != NULL)
    {
      addRef();
    }
  }
  T& operator*(){return *mptr;}
  const T& operator*()const{return *mptr;}
  T* operator->(){return mptr;}
  const T* operator->()const{return mptr;}

  void addRef(){mHeapTable.addRef(mptr);}
  void delRef(){mHeapTable.delRef(mptr);}
  int getRef(){return mHeapTable.getRef(mptr);}
private:
  T *mptr;
   static CHeapTable &mHeapTable;
};
template<typename T>
CHeapTable& CSmartPtr<T>::mHeapTable = CHeapTable::getInstance();