Chapter 9 Linked Lists
Linked List:

The length of the list can grow without limits by adding new links.

New items can be inserted into list by merely breaking a connection, adding a new link, and restoring the connection.

Items are removed from the list by breaking two connections, removing a link, and then reconnecting the chain.

head -> 74 -> 60 -> 25 -> 82 -> 65 -> 23 -> NULL

head -> 74 ->60-> 25 -> 82 -> 65 -> 23 -> NULL
           ------->   Delete 60

head -> 74 -------> 25 -> 82 -> 65 -> 23 -> NULL
                     \ /
                      |
                      50   Insert 50

head -> 74 -> 25 -> 50 -> 82 -> 65 -> 23 -> NULL

• If a list does not contain a node, the head pointer is null.

front ---> NULL   (Empty List)
node<T> * front = NULL;

• If a list is stored in an array, the elements are order from the first position to the last position.
• If a list is stored in a stack, the elements are order from the bottom of stack to the top of stack.
• If a list is stored in a linked list, the order does not exist like an array.

Compare a single linked list with a double linked list:

• the code to check if the list is empty:
• Single Linked List:
front == NULL
• Double Linked List
header->next == header    or
header->prev == header
• default constructor:
• Single Linked List:

      node() : next(NULL)
      {}
• Double Linked List
   dnode()
  {
   next = this;
   prev = this;
  }
• Each update(Insert or Delete a node):
• Single Linked List:
update next
• Double Linked List
update next and prev

Look at coding in the book:
The following are information from your textbook:
program 9.1
program 9.2
program 9.3
program 9.4