Chapter 19, Problem 5FTE

Explanation of Solution

Purpose of the given code:

The given code is used to remove the last node from a nonempty doubly linked list “myList”.

Given code:

/* The reference last points to the last node in a nonempty doubly linked list. Remove the last node from the list */

last = last.prev;

Error in the given code:

First, user needs to check if the list is nonempty, and also have to undo the removed node, and then set the next reference of the new last node to null.

/* If the last node is equal to "null", then */

if (last == null)

  /* Set "first" to "null" */

  first = null;

//Otherwise

else

{

  /* Set the reference "prev" of last node to "null" */

  last.next.prev = null;

  /* Set next node of last to "null" */

  last.next = null;

}

Corrected code:

/* The reference last points to the last node in a nonempty doubly linked list...