Haskell - Seven languages in Seven Weeks

Day1.hs

-- Question 1

	allEven :: [Integer] -> [Integer]
	allEven [] = []
	allEven (h:t) = if even h then h:allEven t else allEven t

	allEven2 :: [Integer] -> [Integer]
	allEven2 list = [a | a <- list, even a]

-- Question 2

	reverse2 [] = []
	reverse2 (h:t) = (reverse t)

	reverse3 list = rev list []
		where 
			rev [] y     = y
			rev (x:xs) y = rev xs (x:y)
			
-- Question 3
	
	let allColours = [(a,b) | a <- colours, b <- colours, a < b]
              where colours = ["black","white","blue","yellow","red"]
              
-- Question 4
       let multiplicationTable = [(a,b,a * b) | a <- [1..12], b <- [1..12] ]
       
-- Question 5

	let colours = ["red", "green", "blue"]
	[(alabama, mississippi, georgia, tennessee, florida) |
	  alabama <- colours,
	  mississippi <- colours,
	  georgia <- colours,
	  tennessee <- colours,
	  florida <- colours,
	  mississippi /= tennessee,
	  mississippi /= alabama,
	  alabama /= tennessee,
	  alabama /= georgia,
	  alabama /= florida,
	  georgia /= florida,
	  georgia /= tennessee]