summer :: [Int] -> Int summer = foldr (-) 0 summel :: [Int] -> Int summel = foldl (-) 0 main :: IO () main = do print (summer [1,2,3]) -- 0-(1-(2-3)) = 0-(1-(-1)) = 2 print (summel [1,2,3]) -- ((0-1)-2)-3 = -6
