import java.util.*;

class ListExp1 {
    public static void main(String[] args) {

	ArrayList<Integer> lst = new ArrayList<Integer>();
        for (int i = 0; i < 3; i ++) {
            lst.add(i*i);
        }

        int j = 0;
        while( j < lst.size() ) {
	    System.out.println( lst.get(j) );
            j ++;
        }

        ListIterator<Integer> itr = lst.listIterator(0);
        while( itr.hasNext() ) {
	    System.out.println(itr.next());
        }

        ListIterator<Integer> itr1 = lst.listIterator(0);
        while( itr1.hasNext() ) {
	    System.out.println(itr1.next());
        }

    

        while( itr.hasPrevious() ) {
            System.out.println(itr.previous());
        }


        
        itr.add(9);
        itr.add(16);
        System.out.println(itr.next());
        itr.set(21);
        System.out.println(itr.previous());

	/*
        System.out.println(itr1.previous()); // This causes an exception
        */
        
        
    }
}