Circular dependencies of declarations

Question

I am trying to implement example of visitor pattern, but I have trouble with circular dependecies of declarations of classes. When I do forward declaration of class Visitor,

Answer 1

I haven't write complex C++ program in a long time but if I remember correctly, you should out the skeleton of those classes in .h file with the same name with this .c file. Then include it into this .c file.

Hope this helps.