/**
 * Interface for Queue
 * Names follow Java standard, but this interface has fewer 
 * methods than Java standard
 * @author gtowell
 * Created: Sep 2019
 * Modified: Oct 20, 2020
 */
 public interface QueueInterface<E> { 
    int size();         // the number of items in q
    boolean isEmpty();  // return true iff q is empty
    E peek();          // return the first item in q
    boolean offer(E e);  // add the item to q
    E poll();        // remove from, and return the first item in q
}