Can you have protected nested classes in C++?

Question

I have a class that only really ever needed by classes in a certain class hierarchy. I wanted to know if it is possible to nest the class in the highest class's protected section and have all the other classes automatically inherit it?

Answer 1

"Inherit" is the wrong word to use since it has a very specific definition in C++ which you don't mean, but yes you can do that. This is legal:

 class A {
   protected:
   class Nested { };
 };

 class B : public A {
   private:
   Nested n;
 };

And code that is not in A or something that derives from A cannot access or instantiate A::Nested.