ITERATOR

package nothing;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.ListIterator;

public class Nothing
{
    public static void main(String[] args)
    {
        ArrayList<String> al = new ArrayList<String>();
        //add elements to array list
        al.add("c");
        al.add("a");
        al.add("e");
        al.add("b");
        al.add("d");
        al.add("f");
        //use iterator to display contents of al
        System.out.println("Original contents of al : ");
        Iterator<String> itr = al.iterator();
        while(itr.hasNext())
        {
            String element = itr.next();
            System.out.println(element+" ");
        }
        System.out.println("");
        //modify objects being iterated
        ListIterator<String> litr = al.listIterator();
        while(litr.hasNext())
        {
            String element = litr.next();
            litr.set(element+"+");
        }
        System.out.println("Modified contents of al : ");
        itr=al.iterator();
        while(itr.hasNext())
        {
            String element = itr.next();
            System.out.println(element+" ");
        }
        System.out.println("");
        //now display the list backward
        System.out.println("Modified list backward : ");
        while(litr.hasPrevious())
        {
            String element = litr.previous();
            System.out.println(element+" ");

        }
        System.out.println("");
    }
}