decimal to binary fraction

decimal-to-binary.rkt

#lang racket/base
(require racket/stream)


;; decimal-to-binary-fraction: positive-real-less-than-1 -> (sequenceof (U 0 1))
;; Computes the binary expansion of the fraction part of a number.
(define (decimal-to-binary-fraction n)
  (let loop ([n n]
             [current-fraction 1/2])
    (cond [(= n 0)
           empty-stream]
          [(>= n current-fraction)
           (stream-cons 1
                        (loop (- n current-fraction)
                              (* 1/2 current-fraction)))]
          [else
           (stream-cons 0
                        (loop n (* 1/2 current-fraction)))])))