chapter6-lab3.hs

module Lab3 where

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-- LIST COMPREHENSIONS
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-- ===================================
-- Ex. 0 - 2
-- ===================================

evens :: [Integer] -> [Integer]
evens xs = [ x | x <- xs, x `rem` 2 == 0]

-- ===================================
-- Ex. 3 - 4 
-- ===================================

-- complete the following line with the correct type signature for this function
squares :: Integer -> [Integer]
squares n = [ x ^ 2 | x <- [1..n]]

sumSquares :: Integer -> Integer
sumSquares n = sum (squares n)

-- ===================================
-- Ex. 5 - 7
-- ===================================

-- complete the following line with the correct type signature for this function
squares' :: Integer -> Integer -> [Integer]
squares' m n = [ x ^ 2 | x <- [n+1..n+m]]

sumSquares' :: Integer -> Integer
sumSquares' x = sum . uncurry squares' $ (x, x)

-- ===================================
-- Ex. 8
-- ===================================

coords :: Integer -> Integer -> [(Integer,Integer)]
coords m n = [ (x, y) | x <- [0..m], y <- [0..n]]