Ch2 Realm of Racket

guessing-game.rkt

#lang racket

(define lower-bound 1)
(define upper-bound 100)

(define (start n m)
  (set! lower-bound (min n m))
  (set! upper-bound (max n m))
  (guess))

(define (guess)
  (quotient (+ lower-bound upper-bound) 2))

(define (smaller)
  (set! upper-bound (max lower-bound (sub1 (guess))))
  (guess))

(define (bigger)
  (set! lower-bound (min upper-bound (add1 (guess))))
  (guess))