package examples;

import java.util.Vector;

public class Queues {
    Vector v = new Vector();

    public void enqueue(Object o) {
        v.addElement(o);
    }

    public Object dequeue() {
        try {
            return v.remove(0);
        } catch (java.lang.ArrayIndexOutOfBoundsException e) {
            return null;
        }
    }

    public static void main(String args[]) {
        Queues q = new Queues();
        q.enqueue("first");
        q.enqueue("second");
        q.enqueue("third");
        for (Object o = q.dequeue(); o != null; o = q.dequeue())
            System.out.println(o);
    }
}