CODEWITHSUNDEEP
haskelltreebinary-tree
Can
Can

Reputation: 15

Binary Expression Tree

i'm very new in haskell and i have a problem. I want to take list for ex. [0,1,0,0,1,1,0,1] and put the elements in a Tree structure which is;

data Tree = Leaf Int | Node String (Tree) (Tree)

so far wrote the below code but it gives an error.

bdd (x:xs)= if elem x [0..9] then Leaf x else Node x (Tree) (Tree)

thank you for your help!

Upvotes: 0

Views: 234

Answers (2)

Netwave
Netwave

Reputation: 42796

You are not using the Tree constructor on the recursive call of your function, bdd should return a Tree, wich is build with Leaf or Node, but notice that Node should be build with 2 trees with also should be built with Leaf or Node, not Tree

bdd :: [Int] -> Tree
bdd (x:xs)= if elem x [0..9] then Leaf x else Node (show x) (bdd xs) (bdd xs)

You should check how you want to properly build the tree, this is just an example.

Upvotes: 2

dfeuer
dfeuer

Reputation: 48631

Your code tries to put x in a Leaf, requiring it to be an Int, and also tries to put out in a Node, requiring it to be a String. Certainly Int and String are different types, so this won't compile. Also, Tree is a type constructor, so you can't use it in terms. What's your code actually supposed to do?

Upvotes: 2

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