请问如何用LISP判断一个整数是奇数还是偶数？

wangph

请问如何用LISP判断一个整数是奇数还是偶数？

龙龙仔

指令: (rem 13 2)
1

指令: (rem 12 2)
0

Andyhon

Tom Smith
(defun evenp (num)  (zerop (logand 1 num)))

michael puckett
(defun IsEven ( x )
   (zerop (rem x 2))
)

(defun IsEven ( x )
   (/= 1 (logand x 1))
)

Bobby Jones
;;;determines if a number is even
;;;returns T if it is and nil if it's not
(defun isEven (number)
  (zerop (rem number 2))
)

Bill Wilkerson
(defun oddp (num) (eq 1 (logand 1 num)))

(defun evenp (num) (not (oddp num)))

Vladimir Nesterovsky
(defun evenp(n)
  (cond
    ((zerop n) T)
    (T (oddp (- n 1)))))

(defun oddp(n)
  (cond
    ((zerop n) nil)
    (T (evenp (- n 1)))))