Pfthb

It is ok to overload assignment operator of a Class A, but not sure if it is allowed to overload assignment operator of pointer type of class A.
is it legitimate question or not...? If yes, how?

For example, I would like to do ref_count++ whenever we have a pointer reference on it below.

class A
 public:
 A()
 ~A()
 int ref_count0;


main()

 A* a1 = new A(); //line 1
 A* a2 = a1; //line 2
 

After execution of line 1, A.ref_count is 1
After execution of line 2, A.ref_count is 2

I believe you mean pointer assignment. Short answer: no, you can't.

It looks like you wan't a reference counted pointer. First lets examine why your solution doesn't work:

1. Here: A* a1 = new A(); you are doing pointer assignment, not class assignment. You cannot overload this operation.


2. In your definition of Class A you implement reference counting. This is not a good solution, what if you want a new class (Class B) that also requires reference counting? You have to implement it all over again. This is not nice or re-usable.

So, what can we do? Well, it depends on why you wan't reference counting. It seems like you wan't self managed memory. Fortunatley, c++ provides a construct for this already. It is std::shared_ptr. You can use it like this:

 std::shared_ptr<A> a1 = std::make_shared<A>(); // Reference count is set at 1
 
 std::shared_ptr<A> a2 = a1; // Reference count is incremented to 2
 // Reference count is decremented to 1
 // Reference count is decremented to 0 and the memory is released.