Should copy constructor be private or public

Question

I am writing an abstract class that will be a parent for several other classes. I am thinking the copy constructor should be made private because you are using an abstract class and there is nothing to copy. However, I am not a 100% sure.

Am I correct and if I am not why should it be public or protected?

Answer 1

The copy constructor should be private if you do not want objects of the class to be copied. Otherwise, it should be public.

Answer 2

I think protected is the best choice: it leaves the decision on whether or not the object is copyable to the derived classes, while prohibiting the copying at the abstract class level, preventing the dreaded object slicing.