Yell implementado.

racket/HtC1x/1b/yell.rkt

@@ -0,0 +1,28 @@
+;; The first three lines of this file were inserted by DrRacket. They record metadata
+;; about the language level of this file in a form that our tools can easily process.
+#reader(lib "htdp-beginner-reader.ss" "lang")((modname yell) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f #t none #f () #f)))
+;; yell.rkt
+
+
+;;
+;; PROBLEM:
+;;
+;; DESIGN a function called yell that consumes strings like "hello" 
+;; and adds "!" to produce strings like "hello!".
+;;
+;; Remember, when we say DESIGN, we mean follow the recipe.
+;;
+;; Leave behind commented out versions of the stub and template.
+
+;; String -> String
+;; Produce string with "!" added to end of supplied string
+(check-expect (yell "hello") "hello!")
+(check-expect (yell "bye") "bye!")
+
+;(define (yell s) "") ; stub
+
+;(define (yell s)     ; template
+;  (... s))
+
+(define (yell s)
+  (string-append s "!"))