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-- Exercise 1
fib :: Integer -> Integer
fib 0 = 0
fib 1 = 1
fib n = (fib (n-1)) + (fib (n-2))
fibs1 :: [Integer]
fibs1 = map fib [0..]
-- Exercise 2
fibs2 :: [Integer]
fibs2 = map fst $ iterate (\l -> ( snd l , snd l + fst l )) (0,1)
-- Exercise 3
data Stream a = Cons a (Stream a)
streamToList :: Stream a -> [a]
streamToList (Cons a s) = a : streamToList s
instance Show a => Show (Stream a) where
show s = show $ take 20 $ streamToList s
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