Exercise 3.81: Exercise 3.6 discussed
generalizing the random-number generator to allow one to reset the
random-number sequence so as to produce repeatable sequences of “random”
numbers.  Produce a stream formulation of this same generator that operates on
an input stream of requests to generate a new random number or to
reset the sequence to a specified value and that produces the desired
stream of random numbers.  Don’t use assignment in your solution.