Rule of Three in C++

Question

I\'ve read that The Rule of Three, What is The Rule of Three? is summarized as follows:

If you need to explicitly declare either the destructor, copy

Answer 1

I am absolutely certain that there is no usage in the application of a copy constructor, i.e., usage of the type Class c(..); Class d(c)

Are you aware that the following code

Foo c;
Foo b = c;

invokes the copy constructor and NOT the assignment operator? I'd implement the copy constructor just to be safe.