Thread: is there a better way to optimise this?

Originally Posted by iMalc

Oh no it's just getting worse - I can't stand it any longer!
This is how to do it, the way you've defined things:

Code:

list_t* Insert(list_t *list, data_t value)
{
	node_t *prev = NULL, *curr = list->head, *ins = malloc(sizeof(node_t));
	while (curr != NULL)
	{
		if (value < curr->data) break;
		prev = curr;
		curr = curr->next;
	}
	if (prev == NULL)
		list->head = ins;
	else
		prev->next = ins;
	if (list->foot == NULL)
		list->foot = ins;
	ins->next = curr;
	ins->data = value;
	return list;
}

Wouldn't list->foot need to be updated even in situations where it's non-NULL? [I'm assuming "foot" is equivalent of "tail" in this case, rather than for example "the first inserted element", as the latter isn't a particularly useful concept as far as I'm aware.

I think the expresson shoudl be "if(curr == NULL)" instead, but I'm not 100% sure. Can you confirm, iMalc?

--
Mats

Originally Posted by matsp

Wouldn't list->foot need to be updated even in situations where it's non-NULL? [I'm assuming "foot" is equivalent of "tail" in this case, rather than for example "the first inserted element", as the latter isn't a particularly useful concept as far as I'm aware.

I think the expresson shoudl be "if(curr == NULL)" instead, but I'm not 100% sure. Can you confirm, iMalc?

--
Mats

Um yeah, good spotting, that's what it should be. Made a mistake in translating my C++ code to his C code.

Originally Posted by iMalc

Um yeah, good spotting, that's what it should be. Made a mistake in translating my C++ code to his C code.

Sure, I make mistakes too, as you may know... :-)

--
Mats

yeh, foot/tail needs to be updated, but so what? it was the algorithm i was looking for... the proccess... of course His program needs to be updated, but really...
He doesn't care and doesn't think about it so anal....

so what do you recommend? code wise?

Well, if the algorithm is "broken", it needs to be fixed, otherwise it's wrong. You'll find that A LOT of us here are anal about getting things right, because there are lots of things that are wrong. If you fix the

Code:

	if (list->foot == NULL)
		list->foot = ins;

into

Code:

	if (curr == NULL)
		list->foot = ins;

then you should be fine. Yes, it's anal, but it's "necessary" to get it right, assuming you do use foot for some purpose.

--
Mats