Convert a decimal number to binary in LISP language

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Taking into account that it is necessary to divide the number by 2 until it is equal to 1, and to reorganize the remains, how this conversion could be made into LISP?

lisp

  • Hello user, I’m not sure about what you need, a whole is a whole indifferent to your representation. Usually we just want to format the number (in a string) on a given basis. If this is the case, in Common Lisp just use the function format - (format nil "~B" 42) = "101010".

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Assuming it is an exercise that needs to follow the reasoning of the statement, follow two examples taken of this page:

(defun dtb (x &optional (callback #'princ))
  (unless (= x 0)
    (dtb (floor x 2) callback)
    (funcall callback (mod x 2))))

and

(defun dtb-collect (x)
  (declare (type fixnum x))
  (do ((x x (floor x 2))
       (list nil (cons (mod x 2) list)))
      ((= x 0) list)))

See comment from @Anthonyaccioly if you do not need the loop as described in the body of the question:

"If this is the case, in Common Lisp just use the format function": (format t "~B~%" 42) = "101010"

Demonstrative link, also kindly provided by Anthony: http://ideone.com/WWg18G

3

One way to convert a number into binary is to be using the function format(as quoted in the commentary of Anthonyaccioly) which is comparable to printf of C.

(format t "~{~&~B~}" '(1 2 10 42 11)) ; 1 2 10 42 11 são os números a converter

The ~B is similar to ~D, but prints on binary basis (base 2) instead of decimal.

Ideone

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