One problem which we see here is that we can use this smart pointer class for a pointer of the Person class only. This means that we have to create a smart pointer class for each type, and that’s not easy. We can solve this problem by making use of templates and making this smart pointer class generic. So let us change the code like this:template < typename T > class SP{ private: T* pData; // Generic pointer to be stored public: SP(T* pValue) : pData(pValue) { } ~SP() { delete pData; } T& operator* () { return *pData; } T* operator-> () { return pData; }};void main(){ SP<PERSON> p(new Person("Scott", 25)); p->Display(); // Dont need to delete Person pointer..}Now we can use our smart pointer class for any type of pointer. So is our smart pointer really smart? Check the following code segment.void main(){ SP<PERSON> p(new Person("Scott", 25)); p->Display(); { SP<PERSON> q = p; q->Display(); // Destructor of Q will be called here.. } p->Display();}Look what happens here. p and q are referring to the same Person class pointer. Now when q goes out of scope, the destructor of q will be called which deletes the Person class pointer. Now we cannot call p->Display(); since p will be left with a dangling pointer and this call will fail. (Note that this problem would have existed even if we were using normal pointers instead of smart pointers.) We should not delete the Person class pointer unless no body is using it. How do we do that? Implementing a reference counting mechanism in our smart pointer class will solve this problem. C++
Topic: Pointers
Explain about generic smart pointer class ?
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