tree.ml

type 'a tree =
  | Empty
  | Node of ('a * 'a tree * 'a tree)

let rec walk_tree f tree =
  match tree with
    | Empty -> ()
    | Node (x, left, right) ->
      f x;
      walk_tree f left;
      walk_tree f right


let tree =
  Node (4,
        Node (2,
              Node (1, Empty, Empty),
              Node (3, Empty, Empty)),
        Node (6,
              Node (5, Empty, Empty),
              Empty)
  )