September 2017 Update

Task/Caesar-cipher/Racket/caesar-cipher-1.rkt

@@ -1,19 +0,0 @@
-#lang racket
-
-(define A (char->integer #\A))
-(define Z (char->integer #\Z))
-(define a (char->integer #\a))
-(define z (char->integer #\z))
-
-(define (rotate c n)
-  (define cnum (char->integer c))
-  (define (shift base) (integer->char (+ base (modulo (+ n (- cnum base)) 26))))
-  (cond [(<= A cnum Z) (shift A)]
-        [(<= a cnum z) (shift a)]
-        [else c]))
-
-(define (caesar s n)
-  (list->string (for/list ([c (in-string s)]) (rotate c n))))
-
-(define (encrypt s) (caesar s 1))
-(define (decrypt s) (caesar s -1))

Task/Caesar-cipher/Racket/caesar-cipher-2.rkt

@@ -1,5 +0,0 @@
-> (define s (encrypt "The five boxing wizards jump quickly."))
-> s
-"Uif gjwf cpyjoh xjabset kvnq rvjdlmz."
-> (decrypt s)
-"The five boxing wizards jump quickly."