/**
 * CSE 373, Spring 2011, Jessica Miller
 * An interface that defines the operations for a Queue ADT for Strings.
 */
public interface StrQueue {
    /** 
     * Tests if the queue is empty.
     */
    public boolean isEmpty();

    /**
     * Inserts an element at the end of the queue.
     */
    public void enqueue(String str);

    /**
     * Deletes and returns the element at the front of the queue.
     * @return the deleted value; null if the queue is empty
     */
    public String dequeue();
}