智能指针shared_ptr代码实现

template<typename T>
class SharedPtr
{
public:
	SharedPtr(T* ptr = NULL):_ptr(ptr), _pcount(new int(1))
	{}

	SharedPtr(const SharedPtr& s):_ptr(s._ptr), _pcount(s._pcount){
		(*_pcount)++;
	}

	SharedPtr<T>& operator=(const SharedPtr& s){
		if (this != &s)
		{
			if (--(*(this->_pcount)) == 0)
			{
				delete this->_ptr;
				delete this->_pcount;
			}
			_ptr = s._ptr;
			_pcount = s._pcount;
			*(_pcount)++;
		}
		return *this;
	}
	T& operator*()
	{
		return *(this->_ptr);
	}
	T* operator->()
	{
		return this->_ptr;
	}
	~SharedPtr()
	{
		--(*(this->_pcount));
		if (*(this->_pcount) == 0)
		{
			delete _ptr;
			_ptr = NULL;
			delete _pcount;
			_pcount = NULL;
		}
	}
private:
	T* _ptr;
	int* _pcount;//指向引用计数的指针
};