In addition to what Jens said, you should probably give a definition of a BST at the top, and give some thought to the question of why a BST is not simply the same thing as a node.
- Jon On Sun, Apr 26, 2020 at 10:36 PM Kristina Marie <kahrend...@gmail.com> wrote: > > Hello, > I am trying to use HtDF to create a function to sort a Binary Search Tree. I > am in an intro class so this may be a simple question. I did the following: > > ;define-struct a node > (define-struct node (left value right)) > ;BTS leafs > (define a-node(make-node null "A" null)) > (define b-node (make-node null "B" null)) > (define e-node (make-node null "E" null)) > (define h-node (make-node null "H" null)) > (define i-node (make-node null "I" null)) > > ;BTS internal > (define c-node (make-node a-node "C" b-node)) > (define j-node (make-node h-node "J" i-node)) > (define k-node (make-node j-node "K" null)) > (define f-node (make-node e-node "F" null)) > (define g-node (make-node f-node "G" k-node)) > > ;Root > (define root (make-node c-node "D" g-node)) > > ; Purpose: sort a binary tree > ; Signature: node -> list > ; Examples: > (check-expect (bst-sort null)(list)) > (check-expect (bst-sort a-node)(list "A")) > (check-expect (bst-sort j-node)(list "H" "I" "J")) > (check-expect (bst-sort root)(list "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" > "K")) > > ;Code > (define (bst-sort nod) > (cond > [(null? nod)(list)] > [(and (null? (node-left nod)) (null?(node-right nod))) (list(node-value > nod))] > [else > (string-append (bst-sort (node-left nod) (list (node-value nod)) > (bst-sort (node-right nod)))) > ] > ) > ) > > I keep getting this test failure: > bst-sort: expects only 1 argument, but found 3 > > It has to due with the two last check-expects failing because of the > highlighted line. > > I ran this same code with integers and removed the string from append and it > passed. Any advice? > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to racket-users+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/e5e05ebe-87ed-4d49-8a18-d3b58bae4e38%40googlegroups.com. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CAKfDxxwOOMxMcmTZm7bYJm6D7vM4w1VjORBxcjypWdUCr%3DRduA%40mail.gmail.com.
