Solve 1.16

4 years ago · ca2a636675
parent d49f5893ae
commit ca2a636675
1 changed files with 4 additions and 7 deletions
--- a/sicp-ex-1.16.rkt
+++ b/sicp-ex-1.16.rkt
@ -1,19 +1,16 @@
-; UNFINISHED
 (define (sqr n)
  (* n n))

 (define (fast-ext-iter number power product)
  (cond ((= power 0) product)
-        ((even? power) (fast-ext-iter number
+        ((even? power) (fast-ext-iter (sqr number)
                                      (/ power 2)
-                                      (if (= product 1)
-                                          (sqr number)
-                                          (sqr product))))
+                                      product))
        (else (fast-ext-iter number
                             (- power 1)
-                             (* power product)))))
+                             (* number product)))))

 (define (fast-ext number power)
  (fast-ext-iter number power 1))

-(fast-ext 2 8)
+(fast-ext 2 5)