i''m designing a GUI for my game which is composed of different classes, all derived from CGUIobject i want to store them into an array (ex: { CGUIbutton x, CGUItextbox t, etc } like a collection in VB how can i store the different classes into an array and at runtime determine for each what type of class it is so i can call it''s specific functions

You have essentially two options here, and both involve storing a collection (eg a vector) of CGuiObject*. You could either:
(1) Use C++ RTTI to determine whether each object is of a particular type, and act accordingly, or
(2) [This is what MFC does] Create your own RTTI system, which can tell you exactly what type it is, and act accordingly.

I would recommend option 1, as 2 is a whole lot of effort (believe me, I''ve done it...)