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From: Philippe TEISSIER <teissier@chez.com>
Newsgroups: comp.lang.beta
Subject: Re: Making a simple program to learn
Date: Thu, 15 Feb 2001 22:26:37 +0100
Organization: University of Nice-Sophia Antipolis
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In this code, the case n < 1 is not seen, so the programm will loop. What
must I add to stop the loop at n<=1
In scheme, the code would look like that:
(define (prod_imp n)
    (if (< n 1)
          1
           (if (= (mod n 2) 1)
               (* n (prod_imp (- n 2)))
                (prod_imp (- n 1)))))

or faster: (apply * (filter odd? (iota 1 n)))

What do you advise me ?

Thanx
Philippe TEISSIER wrote:

> Hi
>
> I 'm learning Scheme, and I visited Beta Homepage because my teacher
> advised me to do so
>
> what would be a small pattern giving the product of the n first odd
> numbers as a result.
>
> I thought of
>
> prod_imp:  (# n: @integer;
>                   enter (n)
>                   (if n mod 2 = 0 then exit (n-1) else exit (n *
> ((n)->prod_imp)) if)
>                   #);
>
> But the compiler is to big to DL for my small modem.
> Is this expression correct, if not, could you explain what correction I
> need to do?
>
> Thanx a lot
>
> Philippe TEISSIER
> philippe.teissier@unice.fr