Write recursive Dr Racket functions to do the following. The functions should wo

Question

Write recursive Dr Racket functions to do the following. The functions should work on all types of lists( not just simple lists of atoms). Document (via direct Dr Racket screens/outputs) both your code and the results of running the test cases.

a) Count how many times an item (atom) appears on a list.

Minimum test cases:

(count 3 '(1 5 6 7 8 3 2 3 )) returns 2

(count dog '(cat bird cat dog frog)) returns 1

(count a '(a(a b ) (c (b c)) ((a))b)) returns 3

(count 3 '(1)) returns 0

(count none '()) returns 0

Explanation / Answer

1. Source code:

(define count
(lambda (a s)
    (cond
      ((empty? s) 0)
      ((equal? a (first s))
       (add1 (count a (rest s))))
      (else (count a (rest s))))))

I don't have dr racket installed on my pc so coudn't upload the output screenshots.

You can try running above code in your dr racket. I am pretty much sure it will work.

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