use Perl

• Memoize and bignum (Score:2)

  by brian_d_foy (44)

  In my Mastering Perl class, I also show Memoize for the recursive solution, and bignum for all the solutions.

  So, are you working on this as an article for TPR? :)
  • Re: (Score:2)

    by ambs (3914)

    Just for fun (after reading http://www.willamette.edu/~fruehr/haskell/evolution.html [willamette.edu]). But if people give me enough feedback, I think I'll write it :)
• shouldn't this be optional (Score:1)

  by link (3402)

  How about

  sub fact
  {
          my ( $n ) = @_;

          my @s = ();
          $s[0] = 1;

          foreach my $m ( 1 .. $n )
          {
                  $s[$m] = 0;
                  for( my $k = $m;$k>=1;$k--)
                  {
                     
• re: How would you write factorial? (Score:1)

  by dug (2501)

  Note that I am more interested in the algorithm than in the golfing or obsfuscation.

  I wouldn't call this golfing or obfuscation. It's another take on the classic recursive algorithm, and might not be interesting. Anyway, here's how I'd write the recursive version:

  
sub factorial {
    my $v = shift;
    return 1 if $v == 1;
    return $v * factorial( $v - 1 );
}


  I like to get the terminating case out of the way early on, and then read the meat of the algorithm (or soy of the al
• reduce (Score:2)

  by bart (450)

  use List::Util qw(reduce);
  sub factorial {
      my $v = shift;
      return reduce { $a * $b } 1 .. $v;
  }

  Too bad it produces spurious warnings:

  Name "main::a" used only once: possible typo at test.pl line 5.
Name "main::b" used only once: possible typo at test.pl line 5.
• Iterative, but not C-ish, but straightforward (Score:1)

  by Aristotle (5147)

  sub factorial {
      my $f = 1;
      $f *= $_ for 2 .. shift;
      $f;
  }
  • Re: (Score:2)

    by Shlomi Fish (918)

    I would write it in a similar way too.