Delete Linked List

Delete the whole list and set the head pointer to NULL. There is a slight complication

inside the loop, since we need extract the .next pointer before we delete the node, since
after the delete it will be technically unavailable.

void DeleteList(struct node** headRef)
{
    struct node* current = *headRef; // deref headRef to get the real head
    struct node* next;

    while (current != NULL)
    {
        next = current->next; // note the next pointer
        free(current); // delete the node
        current = next; // advance to the next node
    }

    *headRef = NULL; // Again, deref headRef to affect the real head back in the caller.
}