code.delx.au - gnu-emacs-elpa/blob - packages/realgud/test/gcd.pl

   1 #!/usr/bin/env perl
   2 use strict;
   3 use warnings;
   4
   5 # GCD. We assume positive numbers
   6 sub gcd($$);
   7 sub gcd($$)
   8 {
   9     my ($a, $b) = @_;
  10     # Make: a <= b
  11     ($a, $b) = ($b, $a) if ($a > $b);
  12
  13     return undef if $a <= 0;
  14     return $a if ($a == 1) or ($b-$a == 0);
  15     return gcd($b-$a, $a);
  16 }
  17
  18 die sprintf "Need two integer arguments, got %d", scalar(@ARGV) unless
  19     @ARGV == 2;
  20 my ($a, $b) = @ARGV[0,1];
  21 printf "The GCD of %d and %d is %d\n", $a, $b, gcd($a, $b);