delete data from linked list

Question

I'm trying to delete from a linked list. But it doesn't seems to be working if i try to delete the first element.

if (found)
{
    if (prev == NULL)
    {
        prev = head;
        prev -> next = curr -> next;
        delete curr;
    }
    else
    {
        prev -> next = curr -> next;
        delete curr;
    }
}

return found;

The findNode functions works if i were to delete from somewhere in the middle or from the tail. But i figured out that if i delete from the tail, i've have to set the next to NULL, am i right?

Can you show the findNode function? Most important is how you pass (and set) the prev and curr arguments. — Some programmer dude
– Some programmer dude, Commented Feb 14, 2013 at 17:39
i you have a header node, why doesn't then prev point to to that header node already after a successful search for first node — Cheers and hth. - Alf
– Cheers and hth. - Alf, Commented Feb 14, 2013 at 17:43
When showing a function, please show the complete function, including the function header. — Some programmer dude
– Some programmer dude, Commented Feb 14, 2013 at 17:45

Some programmer dude · Accepted Answer · 2013-02-14 17:43:19Z

1

The problem is probably that you don't actually change the head to point to the new head of the list. You have to change the head:

if (prev == NULL)
{
    head = head->next;  // Set `head` to point to the next node, i.e. the new `head`
    delete curr;
}

answered Feb 14, 2013 at 17:43

Some programmer dude

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1 Comment

win Over a year ago

gosh what a dumb mistake i did there. thanks for the help guys! solved. i changed prev = head; prev -> next = curr -> next; to head = curr -> next;

Ed Heal · Accepted Answer · 2013-02-14 17:45:39Z

0

Assuming that findNode is correct and sets prev to the node before curr (might want to consider a doubly linked list) then

   if (prev == NULL)
   {
      prev = head;
      prev -> next = curr -> next;
      delete curr;
   }

is incorrect. Since when prev is NULL it is the head node that is the one found.

So the code should be

   if (prev == NULL)
   {
      head = head->next;
      delete curr;
   }

answered Feb 14, 2013 at 17:45

Ed Heal

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