Thread: free()ing a list

>why is the output different?
Because the first function doesn't end up setting root to null, the second does. Your print function no doubt tests for a null list and prints an appropriate message if the root is null.

>which function should i use, or are they both ok?
They're both fine for releasing the memory in a list, but you should consider what happens if you try to use the root after calling freelist. A good idea would be to have a list structure rather than just a simple node as your list so that you can maintain a consistent state without having to rely on pointers to pointers, like so:

Code:

struct list {
  struct node *root;
  /* Other handy stuff */
};

Then you can define freelist like this:

Code:

void
freelist(
  struct list *list
  )
{
  if (list && list->root) {
    struct node *index, *save;
    for (index = list->root; !index; index = save) {
      save = index->next;
      free(index);
    }
    list->root = NULL;
    /* Reset other handy stuff */
  }
}

>you meant
Yes, I did. Thank you. That's the result of writing the function my way originally and then hastily changing it to mirror how you wrote it.