Ethiopian multiplication: Difference between revisions

=={{header|Perl}}==

<lang perl>use strict;

sub halve { return int((shift) / 2); }

sub double { return (shift) * 2; }

sub iseven { return ((shift) & 1) == 0; }

sub ethiopicmult

{

my ($plier, $plicand, $tutor) = @_;

print "ethiopic multiplication of $plier and $plicand\n" if ($tutor);

my $r = 0;

while($plier >= 1)

{

$r += $plicand if (!iseven($plier));

if ($tutor) {

print "$plier, $plicand " . (iseven($plier) ? " struck" : " kept") . "\n";

}

$plier = halve($plier);

$plicand = double($plicand);

}

return $r;

}

print ethiopicmult(17,34, 1) . "\n";</lang>