Some answers of the homework in the slides

gistfile1.hs

-- http://koko-u.github.com/haskell_book_reading/#25

import Data.Char (toUpper, intToDigit, isSpace)
import Data.List (isInfixOf, nub)
import Numeric (showIntAtBase)

upperCase :: String -> String
upperCase = map toUpper

removeSpaces :: String -> String
removeSpaces = filter (not . isSpace)

-- cover almost equals isInfixOf
cover :: Eq a => [a] -> [a] -> Bool
cover = flip isInfixOf

uniq :: Eq a => [a] -> [a]
uniq = nub

-- http://stackoverflow.com/questions/1959715/how-to-print-integer-literals-in-binary-or-hex-in-haskell
binExp :: Int -> String
binExp x = showIntAtBase 2 intToDigit x ""

hanoi = undefined -- skip at the moment

fib :: Int -> Integer
fib n = fibs !! n
  where fibs :: [Integer]
        fibs = 0 : 1 : zipWith (+) fibs (tail fibs)