Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uunet!tcs!nujoizey!gwu
From: gwu@nujoizey.Berkeley.EDU (George Wu)
Newsgroups: comp.lang.c++
Subject: Re: Again: Pointer to methods ?
Keywords: Pointers to methods
Message-ID: <958@tcs.tcs.com>
Date: 14 Aug 90 19:00:39 GMT
References: <2292@zgdvda.zgdvda.uucp>
Sender: usenet@tcs.com
Reply-To: gwu@nujoizey.Berkeley.EDU (George Wu)
Lines: 44

In article <2292@zgdvda.zgdvda.uucp>, dingelde@viktoria.grz (Dennis
Dingeldein) writes:
|> // class Menu provides a pulldown functionality
|> class Menu {
|> 
|> public:
|> 	SetPointer( ???? ); // the method ???? will be called if any
|> 			    // Menu Entry is selected (not senseful, I know)
|> 	Start(); // display and start the interaction with the menu
|> 	...
|> };
|> 
|> // class Circle is unknown class, here only for the example visible
|> // it provides the output behaviour of a circle.
|> class Circle {
|> 
|> public:
|> 	Draw(); // displays the circle
|> };
|> 
|> // main shows a menu and draws the circle on selection
|> main() {
|> 	Menu MyMenu( "Draw Circle" );
|> 	Circle MyCircle( ... );
|> 
|> 	MyMenu.SetPointer( MyCircle::Draw( ... ) );
|> 
|> 	// If the User selects an entry , the circle is drawn!
|> 	Menu.Start();
|> }

     We do similar stuff in some of our code.  For us, class Circle and all
similar classes inherit from a base class, say class Callable.  Then the
Menu::SetPointer() argument is just a pointer to a member function of class
Callable.  The parameters passed to the to be invoked later function are
of course fixed.

							George


----
George J Wu                           | gwu@tcs.com or ucbcad!tcs!gwu
Software Engineer                     | 2121 Allston Way, Berkeley, CA, 94704
Teknekron Communications Systems, Inc.| (415) 649-3752