Programming Praxis

6 Responses to “Slots”

1. Programming Praxis – Slots « Bonsai Code said

   January 14, 2011 at 10:54 AM

   […] today’s Programming Praxis exercise, our goal is to create a game that simulates a slot machine. […]
2. Remco Niemeijer said

   January 14, 2011 at 10:57 AM

   My Haskell solution (see http://bonsaicode.wordpress.com/2011/01/14/programming-praxis-slots/ for a version with comments):

   import Control.Monad
   import Data.List
   import System.Random
   import Text.Printf
   import Text.Read.HT
   
   pull :: Int -> IO Int
   pull n = do ws <- replicateM 3 $ randomRIO (0,5)
               putStrLn . unwords $ map (wheel !!) ws
               result . group $ sort ws where
       wheel = words "BAR BELL ORANGE LEMON PLUM CHERRY"                
       result [[0,0,0]] = win "JACKPOT" 101
       result [_]       = win "TOP DOLLAR" 11
       result [[0,0],_] = win "DOUBLE BAR" 6
       result [_,_]     = win "DOUBLE" 3
       result _         = printf "YOU LOSE $%d\n" n >> return (-n)
       win msg d = printf "***%s***\nYOU WIN $%d\n" msg (n*d) >> return (n*d)
   
   prompt :: IO Int
   prompt = do putStr "ENTER YOUR BET: "
               maybe prompt check . maybeRead =<< getLine where
       check bet | bet < 0   = prompt
                 | bet > 100 = putStrLn "HOUSE LIMIT $100" >> prompt
                 | otherwise = return bet
   
   main :: IO ()
   main = instructions >> loop 0 where
       instructions = putStrLn "WELCOME TO THE CASINO\n\
           \BET IN INCREMENTS OF $1 FROM $1 TO $100\n\
           \BET $0 WHEN YOU ARE FINISHED"
       loop purse = prompt >>= \bet -> if bet == 0 then quit purse
           else fmap (+ purse) (pull bet) >>= \n -> status n >> loop n
       status n | n > 0     = printf "YOU HAVE $%d\n" n
                | n < 0     = printf "YOU OWE $%d\n" (-n)
                | otherwise = putStrLn "YOU ARE EVEN"
       quit total | total > 0 = printf "COLLECT $%d FROM THE CASHIER\n" total
                  | total < 0 = printf "PLACE $%d ON THE KEYBOARD\n" (-total)
                  | otherwise = putStrLn "YOU BROKE EVEN"
   
3. Graham said

   January 17, 2011 at 4:21 AM

   My Python solution. Like the Haskell above, I factored out the _win
procedure. I'm not terribly happy with the maze of ifs and elifs my code grew
into, but it'll do.

   #!/usr/bin/env python
   from random import randrange
   WHEEL = ["BAR", "BELL", "ORANGE", "LEMON", "PLUM", "CHERRY"]

   def display_instructions():
   print "WELCOME TO THE CASINO"
   print "BET IN INCREMENTS OF $1 FROM $1 TO $100"
   print "BET $0 WHEN YOU ARE FINISHED"
   return

   def pull(n):

   def _win(msg, d):
   print "***{0}***".format(msg)
   print "YOU WIN ${0}".format(n * d)
   return n * d

   x, y, z = randrange(6), randrange(6), randrange(6)
   print WHEEL[x], WHEEL[y], WHEEL[z]
   if x == y == z == 0:
   return _win("JACKPOT", 101)
   elif x == y == z:
   return _win("TOP DOLLAR", 11)
   elif x == y == 0 or x == z == 0 or y == z == 0:
   return _win("DOUBLE BAR", 6)
   elif x == y or x == z or y == z:
   return _win("DOUBLE", 3)
   else:
   print "YOU LOSE ${0}".format(n)
   return -n

   def play():
   display_instructions()
   bet, purse = 1, 0
   while bet != 0:
   bet = raw_input("ENTER YOUR BET:\t")
   try:
   bet = int(bet)
   except ValueError:
   continue
   if bet > 100:
   print "HOUSE LIMIT $100"
   continue
   elif 1 <= bet <= 100:
   purse += pull(bet)
   if purse > 0:
   print "YOU HAVE ${0}".format(purse)
   elif purse < 0:
   print "YOU OWE ${0}".format(-purse)
   else:
   print "YOU ARE EVEN"
   if purse < 0:
   print "PLACE ${0} ON THE KEYBOARD".format(-purse)
   elif purse > 0:
   print "COLLECT ${0} FROM THE CASHIER".format(purse)
   else:
   print "YOU BROKE EVEN"
   return

   if __name__ == "__main__":
play()

4. Graham said

   January 17, 2011 at 4:24 AM

   Oh no! I had a couple typos (messed up closing the code tag, and extra ” in ) in the comment above. Apologies!
5. uberlazy said

   January 31, 2011 at 10:20 PM

   Waddling through old code is fun, but I feel this exercise isn’t all it could have been. Slot machines are based on interesting statistical models that keep the game addictive while ensuring the House wins. In that vein, I modified the original task and created a weighted slot machine. I know it doesn’t earn me brownie points, but I hope someone finds it interesting or fun.

   I also took the betting out of it so I can just hit the spin key mindlessly, like on a real machine :)

   http://paste.lisp.org/display/119226
6. uberlazy said

   January 31, 2011 at 10:25 PM

   … incidentally, selecting a random wheel stop is a variant of the algorithm for selecting fortunes from the exercise #192.