even or odd...

is there a way to determine if a number is even or odd... i want to have my
routine do one thing if the number is even and another if it is odd...

 

(zerop (rem n 2)) ?

 

Take your pick:

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

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

etc ...

is there a way to determine if a number is even or odd... i want to have my
routine do one thing if the number is even and another if it is odd...

 

thanks...

 

You're welcome. If you search the ngs I think you'll find versions more
elegant than these two ... Tony, Doug etc. usually come up with ridiculously
elegant / succinct functions.

thanks...

 

Well, you could do

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

but that's no more succint than the first test suggested.. You can get a 1
or 0 test result from boole, rem, or logand, but I don't know a way other
than zerop to translate that to the desired t or nil return.