The following sequence of methods are to be invoked on an initially empty queue. Draw the state of the queue after each step. Indicate what is returned by any methods that return values. There is no...

The following sequence of methods are to be invoked on an initially empty queue. Draw the state of the queue after each step. Indicate what is returned by any methods that return values.

There is no method in our Queue interface which is equivalent to the peek() method in the Stack interface. Devise one and add it to the Queue interface. Be sure to specify whether it returns the front or the back element of the Queue