متن اصلی - انگلیسی - פתרון בעיה במחשבים

I think the problem may lie in the fact that you have included (Umar1.h) in the (Umar.h) file. This causes the problem because the (umar1.h) defines the class (Cmar1) which is a decendant of ((Cmar), which is declared in (umar.h.) Now(because you have included (umar1.h) above the declaration for the decendant class (Cmar), the compiler has no idea what a (Cmar )is when it comes to the declaration for (Cmar1.
Try removing the include for (Umar1.h) from umar.h) and betcha that'll do 'er.