invert binary tree

invert-binary-tree.rkt

@@ -0,0 +1,23 @@
+#lang sicp
+(define (make-tree entry left right) (cons entry (cons left  right)))
+(define (left-branch tree) (cadr tree))
+(define (right-branch tree) (cddr tree))
+(define (entry-tree tree) (car tree))
+(define lefts-left (make-tree 'c '() '()))
+(define rights-left (make-tree 'q '() '()))
+(define l1 (make-tree 'f lefts-left '()))
+(define r1 (make-tree 'z rights-left '()))
+(define t1 (make-tree 'm l1 r1))
+
+(left-branch t1)
+(right-branch t1)
+
+t1
+
+(define (invert-tree tree)
+  (cond ((null? tree) '())
+        ((cons (entry-tree tree)
+               (cons (invert-tree (right-branch tree))
+                     (invert-tree (left-branch tree)))))))
+
+(invert-tree t1)