So, what happened? 1

An indication that more objects were destroyed than created, was caused by the program creating two additional objects using the copy constructor. Since the copy constructor didn't announce it's activity or add to num_strings, we missed it.
Solution? create an explicit copy constructor with ++num_strings in it.

An indication that more objects were destroyed than created, was caused by the program creating two additional objects using the copy constructor. Since the copy constructor didn't announce it's activity or add to num_strings, we missed it.