Parni cifri na parni pozicii

for more codes >> http://adyou.me/qtCb

defun parni(lista)
   (parniPom lista 1)
)
(defun parniPom (lista brojac)
   (cond
       ((null lista) nil)
       ((proveriParni (car lista) 1) (cons brojac (parniPom (cdr lista) (+ 1 brojac))))
       (t(parniPom (cdr lista) (+ 1 brojac)))
   )
)
(defun proveriParni (n i)
    (cond
        ((= 0 n) t)
        ((and smile emoticon (mod i 2) 0) (not smile emoticon (mod (mod n 10) 2) 0))) nil)
        (t(proveriParni (floor(/ n 10)) (+ i 1)))
    )
)
(print(parni '(21 12 33 422 13 4215)))
;1 4