my @pages = (
	'frontpage.html',
	'aboutus.html',
	'login.html',
);	# extra comma is there so adding new pages is easier

my $num = CGI::param('Num') || 1;
page($num - 1);		# or put a dummy at the start of @pages

sub page {
	$| = 1;
	my $num = shift;
	if (open(FILE, $pages[$num])) {
		print while <FILE>;
	}
}