import java.util.*;

class LinkedListEnumerator implements Enumeration {
    protected LinkedListEntry pos;

    public LinkedListEnumerator(LinkedList list) {
        pos = list.start;
    }

    public boolean hasMoreElements() {
        return (pos != null);
    }

    public Object nextElement() {
        // Make sure the current object is valid
        if (pos == null)
            throw new NoSuchElementException();

        // Increment the list and return the object
        LinkedListEntry tmp = pos;
        pos = pos.next;
        return tmp.val;
    }
}