Empty List

A linked list without any nodes is called empty. A sensible implementation of any type of data structure must allow it to be empty.

Here is a tester method for the LinkedList class that creates an empty list:

// LinkedListTester.java
//
public class LinkedListTester
{
  public static void main( String[] args )
  {
    // create an empty linked list
    LinkedList list = new LinkedList();  
  }
}

Running the program prints nothing, but behind the scenes an empty linked list is constructed (and then becomes garbage when the program ends.)

C:\JavaSource> javac Node.java LinkedList.java LinkedListTester.java
C:\JavaSource> java  LinkedListTester
C:\JavaSource>

After an empty list has been created, nodes can be linked into a chain using list.insertFirst() .

QUESTION 3:

Complete the isEmpty() method of LinkedList .

  // Determine if the List is empty
  public boolean isEmpty()
  {
     // return true for an empty list, otherwise return false
  }