]> On 23.12.2003 11:00, Tyler Eaves wrote: > (* primes2.ml > Prime number generator, take 2 > Tyler Eaves <tyler@ml1.net> > *) > > exception Not_prime;; > exception Its_Prime;; > > let rec isprime n primes = ( > try > List.iter (fun x -> if n mod x = 0 then raise Not_prime else if sqrt > (float_of_int n) < (float_of_int x) then raise Its_Prime else ()) primes; > Printf.printf "%d is PRIME!\n" n; > isprime (n+2) (List.concat [primes; [n]]) > with > Not_prime -> isprime (n+2) primes > | Its_Prime -> (Printf.printf "%d is PRIME!\n" n; > isprime (n+2) (List.concat [primes; [n]])) > );; > > isprime 3 [2];; Minor thing - instead of "List.concat [primes; [n]]", you can write just "primes @ [n]" ("@" is an infix list append operator). Also, List.iter is still somewhat imperative. Here is a slight modification: let rec list_exists f n = function [] -> false | hd :: _ when hd > n -> false | hd :: tl -> f hd && (list_eists f n tl) ;; let rec print_primes n primes = let limit = int_of_float (sqrt (float_of_int n))) in if list_exists (fun x -> n mod x = 0) limit primes then print_primes (n + 2) primes else begin Printf.printf "%d is PRIME!\n" n; print_primes (n+2) (primes @ [n]) end;; print_primes 3 [2];; -- Aleksey Nogin Home Page: http://nogin.org/ E-Mail: nogin@cs.caltech.edu (office), aleksey@nogin.org (personal) Office: Jorgensen 70, tel: (626) 395-2907 ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners