Question

I’m studying C++ on my own time, and writing a linked list to try and get the hang of it. I’m worried about the way I’ve come up to delete the object. It’s a singly linked list. Here’s the destructor:

template <typename T>
LinkedList<T>::~LinkedList() 
{
  Node<T> * current = this->first;
  do {
    Node * temp = current->next;
    delete current; // THIS JUST MIGHT BE A TERRIBLE IDEA!!!
    Node * current = temp; // new current-- might work with the current
                           // delete a line above
  } while (current->next != 0); // need to leave this->last so that I don't
                                // delete it twice in the next line.
                                // Just realized I'm deleting this->first, then 
                                // in the next line [implicitly] deleting it again!
                                // 
  delete this;
}

I create a pointer to the first node in the list, create a temporary pointer to the next node, delete the first pointer, create a new pointer with the same name, which then loops back. After it’s done, it deletes the ‘this’ pointer.

I’m sure you can see why I’m worried with the way I create a new pointer with the same name as a deleted pointer.

Answer 1

1. Don’t delete this in the destructor.
2. If Node is a template, then you need to write Node<T> in all of those definitions.
3. Don’t redefine current, just assign it a new value.

Other than that, I don’t see any other problems in this snippet.