tasks a-s

Task/Repeat-a-string/Racket/repeat-a-string-1.rkt

@@ -0,0 +1,4 @@
+; fast
+(define (string-repeat n str)
+  (apply string-append (make-list n str)))
+(string-repeat 5 "ha") ==> "hahahahaha"

Task/Repeat-a-string/Racket/repeat-a-string-2.rkt

@@ -0,0 +1,7 @@
+; memory efficient
+(define (string-repeat n string)
+  (with-output-to-string
+   (λ ()
+     (for ([_ (in-range n)])
+       (display string)))))
+(string-repeat 5 "ha") ==> "hahahahaha"

Task/Repeat-a-string/Racket/repeat-a-string-3.rkt

@@ -0,0 +1 @@
+(make-string 5 #\*) => "*****"