sub change {
    my $arr = shift;
    $_++ for @$arr;
}
my $x = 1;
my $y = 2;

change([ $x, $y ]);
print "($x) ($y)\n";

##</code><code>##

sub change {
	my $arr = shift;
	$$_++ for @$arr;
}

my $x =  1;
my $y = 2;
change([ \$x, \$y ]);
print "($x) ($y)\n";