Leon Breedt wrote:
> i'm working on a doubly-linked list at the moment, just one or two questions:
>
> i looked at the way the doubly linked list is implemented in glib,
What is glib?
> and it
> seems to me a way to create a list is to not call plist_alloc() explicitly,
> but use plist_append(), and have that do the allocating. and, so far, it
> works.
>
> now, my question: should i free() the data items in the list cleanup code, or
> leave that to the part of my program where i allocated the data items? i.e.
> in the part where i allocated the data items, iterate through the list and
> free() all my data items? that seems to me the more logical approach.
> (i.e. when *data is not a pointer, but for example a static struct that i added
> by calling plist_append(list, &struct_name);
In general, it's a bad idea to mix dynamically allocated data with
statically allocated data in complex structures. It means that you
can't just write a free_list() function; the code which frees the list
has to know which pointers it can call free() on.
> i think this code is working, because i can successfully traverse the list
> forwards and backwards.
>
> heres part of the code:
[snip]
> PList* plist_append(PList *list, ppointer data)
> {
> PList *new_item, *last_item;
>
> new_item = plist_alloc();
> new_item->data = data;
>
> if (list) {
> last_item = plist_last(list);
> last_item->next = new_item;
> new_item->prev = last_item;
> return list;
> } else return new_item;
>
> }
When working with linked lists, it is more usual (and quicker) to
insert at the front of the list, e.g.
PList* plist_prepend(PList *list, ppointer data)
{
PList *new_item;
new_item = plist_alloc();
new_item->data = data;
new_item->next = list;
if (list)
list->prev = new_item;
return new_item;
}
--
Glynn Clements <[EMAIL PROTECTED]>
