MClass

Hi all,
I am beginner in symbian and have a confussion that If we are deriving over class from some observer that means we are using some virtual function of that abstract class . If I am not derive the class form observer and define Abstract class just above my class then need to be pass observer like (

(1) class MCoeControlObserver:CBase
public:
{

virtual void HandleControlEventL(CCoeControl* aControl,TCoeEvent aEventType)=0;
};
//
insted
(2)class CViewAppContainer : public CCoeControl, MCoeControlObserver

Problem is here //
how can i use (1) insted of (2)