Scheme Turtle 5

Random-Walk

Diese Prozedur verdeutlich den Weg in den rekursiven Abstieg und zurück, wie er bei echter Rekursion stattfindet, grafisch.

<eval> (define random</eval>

 (random-maker 19768116))  ;; Anfangswert verändern!

(clear canvas4) (move turtle4 200 310) (pencolor turtle4 0 0 200)

(define random-walk

 (lambda (angle length n turtle)
   (if (= n 0)
       ;(penerase turtle)
       (pencolor turtle4 220 0 0)
       (begin          
         (forward turtle length)
         (right turtle angle)
         (random-walk (+ 5 (random angle))(+ 5 (random length)) (- n 1) turtle)
         ;(sleep-for-a-while 0.01)
         (left turtle angle)
         (backward turtle length)))))

(random-walk 360 20 1000 turtle4)

(define t (clone turtle)) (hide t) (forward t 50) (right t 90) (forward t 50) (show t)

(setangleto t turtle)