guessing_game.exs

# Programlog Elixir - exercise: ModulesAndFunctions-6
#
# Example:
#   iex> GuessingGame.search(279, 1..1000)
#   is it 500?
#   is it 250?
#   is it 375?
#   is it 312?
#   is it 281?
#   is it 265?
#   is it 273?
#   is it 277?
#   is it 279?
#   Winner, winner chicken dinner!
#   :ok

defmodule GuessingGame do

  def midpoint(lo..hi) do
    div(lo + hi, 2)
  end

  def search(actual, range) do
    guess = midpoint(range)
    IO.puts "is it #{guess}?"
    search(actual, range, guess)
  end

  def search(actual, _lo..hi, guess)
    when guess < actual do
      search(actual, guess..hi)
  end

  def search(actual, lo.._hi, guess)
    when guess > actual do
      search(actual, lo..guess)
  end

  def search(actual, _range, guess)
    when guess == actual do
      IO.puts "Winner, winner chicken dinner!"
  end

end

guessing_game.scm

; Programming Elixir - exercise: ModuleAndFunctions-6 in Gauche Scheme
;
; gosh> (use guessing-game)
; gosh> (search 279 1 1000)
; is it 500?
; is it 250?
; is it 375?
; is it 312?
; is it 281?
; is it 265?
; is it 273?
; is it 277?
; is it 279?
; Winner, winner chicken dinner!

(define-module guessing-game
  (export search)

  (define (midpoint lo hi)
    (quotient (+ lo hi) 2))

 (define (search actual lo hi)
   (let ((guess (midpoint lo hi)))
     (print "is it " guess "?")
     (cond ((< guess actual)
            (search actual guess hi))
           ((> guess actual)
            (search actual lo guess))
           (else
             (print "Winner, winner chicken dinner!"))))))