一种智能指针的实现方式

#include
#include
using namespace std;
#define TEST_SMARTPTR

class Stub
{
public:
	void print(){
		cout << "Stub:print" << endl;
	}
	~Stub(){
		cout << "Stub:Destructor" << endl;
	}
};

template
class SmartPtr
{
private:
	T* ptr;
	size_t* pUse;
public:
	SmartPtr(T* p = 0) :ptr(p), pUse(new size_t(1)){}
	SmartPtr(const SmartPtr& src) : ptr(src.ptr), pUse(src.pUse){
		
		++*pUse;
	}
	SmartPtr& operator=(const SmartPtr& rhs){
		++*rhs.pUse;
		decrUse();
		ptr = rhs.ptr;
		pUse = rhs.pUse;
		return *this;
	}
	T* operator->(){
		if (ptr)
			return ptr;
		throw std::runtime_error("access through NULL pointer");
	}
	const T* operator->()const{
		if (ptr)
			return ptr;
		throw std::runtime_error("accessthroughNULLpointer");
	}
	T& operator*(){
		if (ptr)
			return *ptr;
		throw std::runtime_error("dereferenceofNULLpointer");
	}
	const T& operator*()const{
		if (ptr)
			return *ptr;
		throw std::runtime_error("dereferenceofNULLpointer");
	}
	~SmartPtr(){
		decrUse();
		#ifdef TEST_SMARTPTR
				std::cout << "SmartPtr:Destructor" << std::endl;//fortesting
		#endif
	}
private:
	void decrUse(){
		if (--*pUse == 0){
			delete ptr;
			delete pUse;
		}
	}
};


int main()
{
	try{
		SmartPtrt();
		
	}
	catch (const exception&err){
		cout << err.what() << endl;
	}
	SmartPtrt1(new Stub);
	SmartPtrt2(t1);
	SmartPtrt3(new Stub);
	t3 = t2;
	t1->print();
	(*t3).print();
	return 0;
}