Iterate through elements of a LinkedList using a ListIterator in Java

Java 8 Object Oriented Programming Programming

A ListIterator can be used to traverse the elements in the forward direction as well as the reverse direction in a LinkedList.

The method hasNext( ) in ListIterator returns true if there are more elements in the LinkedList while traversing in the forward direction and false otherwise. The method next( ) returns the next element in the LinkedList and advances the cursor position.

The method hasPrevious( ) in ListIterator returns true if there are more elements in the LinkedList while traversing in the reverse direction and false otherwise. The method previous( ) returns the previous element in the LinkedList and reduces the cursor position backward.

A program that demonstrates this is given as follows.

Example

Live Demo

import java.util.ListIterator;
import java.util.LinkedList;
public class Demo {
   public static void main(String[] args) {
      LinkedList<String> l = new LinkedList<String>();
      l.add("Andy");
      l.add("Sara");
      l.add("James");
      l.add("Betty");
      l.add("Bruce");
      ListIterator li = l.listIterator();
      System.out.println("The LinkedList elements in the forward direction are: ");
      while (li.hasNext()) {
         System.out.println(li.next());
      }
      System.out.println("\nThe LinkedList elements in the reverse direction are: ");
      while (li.hasPrevious()) {
         System.out.println(li.previous());
      }
   }
}

Output

The output of the above program is as follows −

The LinkedList elements in the forward direction are:
Andy
Sara
James
Betty
Bruce

The LinkedList elements in the reverse direction are:
Bruce
Betty
James
Sara
Andy

Now let us understand the above program.

The LinkedList is created and LinkedList.add() is used to add the elements to the LinkedList. A code snippet which demonstrates this is as follows

LinkedList<String> l = new LinkedList<String>();

l.add("Andy");
l.add("Sara");
l.add("James");
l.add("Betty");
l.add("Bruce");

Then the ListIterator interface is used to display the LinkedList elements in the forward and reverse direction. A code snippet which demonstrates this is as follows

ListIterator li = l.listIterator();
System.out.println("The LinkedList elements in the forward direction are: ");
while (li.hasNext()) {
   System.out.println(li.next());
}
System.out.println("\nThe LinkedList elements in the reverse direction are: ");
while (li.hasPrevious()) {
   System.out.println(li.previous());
}

Ankith Reddy

Published on 18-Jan-2019 05:55:32

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