Using binary search tree with custom data types?

Question

I've create a binary search tree:

data SearchTree a = Empty | Node a (SearchTree a) (SearchTree a) deriving (Show, Eq, Ord)

insertTreeElements :: (Ord a) => a -> SearchTree a -> SearchTree a --Create    binary tree input method
insertTreeElements x Empty = Node x Empty Empty
insertTreeElements x (Node a left right)
   | x == a     = Node x left right
   | x < a  = Node a (insertTreeElements x left) right
   | x > a      = Node a left (insertTreeElements x right)

makeTree :: (Ord a) => (a -> SearchTree a -> SearchTree a) -> SearchTree a -> [a] -> SearchTree a --Create binary tree
makeTree iTE Empty li = foldr iTE Empty li

I'm trying to pass in the following list:

Type Age = Int
mylist = [Age 12, Age 100, Age 2, Age 3, Age 43]

However the output is not correct, it does not order the tree based on the size of the ages? How do I need to edit the insertTreeElements to allow it to work with 'Age x'?

Daniel Wagner · Accepted Answer · 2016-09-25 17:38:58Z

1

Probably the biggest problem you have is this one:

   | x > a      = Node a left (insertTreeElements x left)

Notice that you write left twice -- presumably one of them should be right.

answered Sep 25, 2016 at 17:38

Daniel Wagner

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