🚀 go-pugleaf

pjl@sparc10.cs.uiuc.edu (Paul Lucas) writes:

>		void Link::DeleteAll() {
>			for ( Link *p = this, *q; p; p = q ) {
>				q = p->next;
>				delete p;
>			}
>		}

You are deleting the first list member using its own DeleteAll method and
the other members using the first member's DeleteAll method.
To see what the problems can arise from this, make DeleteAll virtual and
redefine it in a subclass:
	class MyLink : Link {
	  void DeleteAll() { ExtraBookkeeping(); Link::DeleteAll(); }
	};

Now MyLink's will be DeleteAll'ed with the wrong method if a plain Link
heads the list. And to make things worse, such a bug would be almost
impossible to find.

However, 
	static Link::DeleteAll(Link* head);
does not have this problem and also note that  `head' can legally be NULL,
solving your original problem.

Anders Munch		|  Department of Computer Science
juul@diku.dk		|  University of Copenhagen, Denmark
"Confused? The thing is to get confused at a higher level" - Jorgen Thorslund