Comments on: Reversing single linked list recursively

By: Igor Kostic

Igor Kostic — Wed, 25 Jun 2008 04:12:16 +0000

I’ guess I’m posting in a wrong thread.
The fix is is for reverse function which is not recursive.
Sorry.

By: Igor Kostic

Igor Kostic — Wed, 25 Jun 2008 04:07:44 +0000

Also interested in swaping elements of SLL and DLL (changing pointers based) and sorting the list using insertion sort after the lists are created.
Anyone worked on this…

By: Igor Kostic

Igor Kostic — Wed, 25 Jun 2008 04:01:49 +0000

I guess I’m to tired. I ment DLList but you have it already here.
Keep up the good work.

By: Igor Kostic

Igor Kostic — Wed, 25 Jun 2008 03:52:44 +0000

There is a typo in the code. Just change

void reverse(struct node** headRef)
to
void reverse(struct Node** headRef)

and in main use
reverse(&h);
instead of
h = recreverse(h);

It runs now.

I’m interested how is it possible to implement function that will reverse the order of the elements of single linked list in one pass without recursion and helper structures.

Anyone?

BTW. Example is very nice.

By: Edna Umali

Edna Umali — Thu, 05 Jun 2008 13:22:34 +0000

i tried but it did not run

By: Dan

Dan — Thu, 08 May 2008 07:14:07 +0000

Why static??

By: ponnada

ponnada — Wed, 30 Apr 2008 04:45:51 +0000

aftab,
I’d not given complete code (only reverse function I gave) not sure how you made a complete piece of code (by writing yours or plugging from other artilces) and not sure how you run, here I’m gibing complete code
complete code
I’m not facing any problems, let me know
if you face any problems further

By: aftab

aftab — Tue, 29 Apr 2008 09:05:06 +0000

I tried the piece of code by “ponnada” on a solaris platform just to see the result……
Segmentation Fault(coredump)
aftab

By: ponnada

ponnada — Thu, 17 Apr 2008 13:56:22 +0000

Hi Aksu,
>The implementation crashes if the list is empty
Yes, it crashes for empty list, it was just an overlook, and simple check should suffice to stop that
>does not work in a multithreaded system
I didn’t claim that it works for multithread env, if I would have intention of multithread env, i would have not used static variables.. surprisingly your version also suffers from empty list crash scenario.
Anyways thanks for pointing out that bug.

By: Aksu

Aksu — Thu, 17 Apr 2008 08:37:09 +0000

I can only guess that the previous comments were ironic…

The implementation crashes if the list is empty, does not work in a multithreaded system, and is far from elegant.

Consider:

/* helper func */
struct Node* reverse(struct Node* current, struct Node* previous)
{
struct Node* next = current->next;
current->next = previous;
if (next)
{
return reverse(next, current);
}
return current;
}

struct Node* reverse(struct Node* aHead)
{
if (aHead)
{
return reverse(aHead, NULL);
{
return NULL;
}