//Removes the last item from a linked list
void linked_list::pop_tail()
{
     ll_item *cursor;
     cursor = head;

     while (true)
     {
          if(cursor->next_item->next_item == NULL)
          {
               delete cursor->next_item;
               cursor->next_item = NULL;

               break;
          }

          cursor = cursor->next_item;
      }
size--;
}