4b ex 1

exercises/Set4b.hs

@@ -21,7 +21,10 @@ import Mooc.Todo
 countNothings :: [Maybe a] -> Int
 countNothings xs = foldr countHelper 0 xs
 
-countHelper = todo
+countHelper :: Maybe a -> Int -> Int
+countHelper x acc = case x of
+  Nothing -> acc+1
+  Just _ -> acc
 
 ------------------------------------------------------------------------------
 -- Ex 2: myMaximum with a fold. Just like in the previous exercise,