Linked Data Structures - Java - page 832

Answers to Self-Test Exercises
1. mustard 1
hot dogs 12
apple pie 1

2. This method has been added to the class LinkedList1 on the accompanying

CD.

public boolean isEmpty( )
{
return (head == null );
}

3. This method has been added to the class LinkedList1 on the accompanying

CD.

public void clear( )
{
head = null ;
}

If you defined your method to remove all nodes using the deleteHeadNode
method, your method is doing wasted work.

4. Yes. If we make the inner class Node a public inner class, it could be used outside

the definition of LinkedList2 , whereas leaving it as private means it cannot be
used outside the definition of LinkedList2 .

5. It would make no difference. Within the definition of an outer class there is full

access to the members of an inner class whatever the inner class member's access
modifier is. To put it another way, inside the private inner class Node , the modi-
fiers private and package access are equivalent to public .

6. Because the outer class has direct access to the instance variables of the inner class

Node , no access or mutator methods are needed for Node .

7. It would be legal, but it would be pretty much a useless method, because you

cannot use the type Node outside of the class LinkedList2 . For example, out-
side of the class LinkedList2 , the following is illegal ( listObject is of type
LinkedList2 ):

Node v = listObject.startNode( ); //Illegal

whereas the following would be legal outside of the class LinkedList2 (although
it's hard to think of anyplace you might use it):

Object v = listObject.startNode( );