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@kwrooijen kwrooijen/dec->bin.scm
Last active Nov 28, 2015

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Decimal to Binary conversion options in Scheme
;; 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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