add up to 4-and-a-half.1
[ozzloy@gmail.com/realm-of-racket-journey] / guess.rkt
1 #! /usr/bin/env racket
2 #lang racket/base
3
4 (define lower 1)
5 (define upper 100)
6
7 (define (guess)
8 (quotient (+ lower upper) 2))
9
10 (define (smaller)
11 (set! upper (max lower (sub1 (guess))))
12 (guess))
13
14 (define (bigger)
15 (set! lower (min upper (add1 (guess))))
16 (guess))
17
18 (define (start n m)
19 (set! lower (min n m))
20 (set! upper (max n m))
21 (guess))