Decimal to Binary conversion options in Scheme
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;; Very clean, but is not tail recursive! | |
(define (dec->bin n) | |
(cond ((zero? n) '()) | |
(else (cons (remainder n 2) | |
(dec->bin (quotient n 2)))))) | |
;; Not so clean, but is tail recursive. | |
(define (dec->bin n) | |
(letrec ((recc (lambda (acc n) | |
(cond ((zero? n) acc) | |
(else (recc (cons (remainder n 2) acc) | |
(quotient n 2))))))) | |
(recc '() n))) | |
;; Not much worse than the cleanest one, but uses optional args. | |
(define* (dec->bin n #:optional (acc '())) | |
(cond ((zero? n) acc) | |
(else (dec->bin (quotient n 2) | |
(cons (remainder n 2) acc))))) | |
(dec->bin 9) ;; => '(1 0 0 1) |
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