🚀 go-pugleaf

In article <chl.720269838@cs.man.ac.uk>, chl@cs.man.ac.uk (Charles Lindsey) writes:
	[text about triple-ref]

|> You can't do this sort of thing in Pascal, but you can do it in C if you are
|> VERY careful.

Indeed, there is the right way:

	struct foo **ptr = &start;
	while (*ptr != NULL)
		ptr = &((*ptr)->next);

and the wrong way:

	struct foo **ptr = &startl
	while (*ptr != NULL)
		*ptr = (*ptr)->next;

the small difference between these is obvious in Algol 68, but in
C you might happily spend half a day wondering why the wrong
way is sucessfully destroying perfectly good lists.

Incidentally, to product the right way originally, I had to puzzle
over the Algol68 version which I knew worked and which I understood,
when I wrote the wrong way in Algol 68 I knew why it didn't work.

C's pointers are a pain in the neck sometimes.

-- 
John Haxby, Definitively Wrong.
Digital				<jch@rdg.dec.com>
Reading, England		<...!uknet!wessex!jch>

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The opinions expressed herein are my own, not my employers.