euclid.pir

# Copyright (C) 2001-2008, Parrot Foundation.
# This program is free software. It is subject to the same
# license as Perl itself.
# $Id$

=head1 NAME

examples/pir/euclid.pir - Euclid's algorithm

=head1 SYNOPSIS

    % ./parrot examples/pir/euclid.pir

=head1 DESCRIPTION

Implements Euclid's algorithm
(http://www.cut-the-knot.org/blue/Euclid.shtml) and uses it to compute
C<gcd(96,64)>.

Knuth, Donald E. I<The Art of Computer Programming Volume 1: Fundamental
Algorithms>. Third Edition. Section 1.1 Algorithm E (Euclid's algorithm)
Page 2:

    I1: m
    I2: n
    I4: r

    E1: Find remainder.
    E2: Is it zero?
    E3: Reduce.

=cut

.sub 'example' :main
        $I1 = 96
        $I2 = 64
        print  "Algorithm E (Euclid's algorithm)\n"
e1:     $I4 = mod $I1, $I2
e2:     unless $I4 goto done
e3:     $I1 = $I2
        $I2 = $I4
        branch e1
done:   print "The greatest common denominator of 96 and 64 is "
        print  $I2
        print  ".\n"
.end

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