//reference : <<Effective C++>> (Third Edition) [美]Scott Meyers 著.侯捷 翻译
/*
  泛化copy构造函数
*/
template<class T>
class SmartPtr{
public:
	template<typename U>
		SmartPtr(const SmartPtr<U>& other)
		:heldPtr(other.get()){/**/}
	T* get()const{return heldPtr;}
	private
		T* heldPtr;
};