smart_ptr.h

class U_Ptr
{
	friend class BHasPtr;
private:
	int *ip;
	size_t use;		// 计数
	
	U_Ptr(int *p): ip(p), use(1) {}
	~U_Ptr() { delete ip; }
};

class BHasPtr
{
public:
	BHasPtr(int *p, int i):ptr(new U_Ptr(p)), val(i) {}
	BHasPtr(const BHasPtr &orig): ptr(orig.ptr), val(orig.val)
	{
		++ptr->use;
	}
	BHasPtr& operator = (const BHasPtr&);

	~BHasPtr()
	{
		if(--ptr->use == 0) delete ptr;
	}

	int *get_ptr() const { return ptr->ip; }
	int get_int() const { return val; }

	void set_ptr(int *p) { ptr->ip = p; }
	void set_int(int i) { val = i; }
	
	int get_ptr_val() const { return *ptr->ip; }
	void set_ptr_val(int val) const { *ptr->ip = val; }
private:
	int val;
//	int *ptr;
	U_Ptr *ptr;
};

BHasPtr& BHasPtr::operator = (const BHasPtr &rhs)
{
	++rhs.ptr->use;
	if(--ptr->use == 0) delete ptr;
	
	ptr = rhs.ptr;
	val = rhs.val;
	return *this;
}