use strict;
use warnings;

search_dir (shift);

sub search_dir {
	my $path = shift;
	my @dir_entries = glob("$path/*");
	foreach my $entry (@dir_entries) {
		print $entry, "\n" if -f $entry;
		search_dir($entry) if -d $entry;
	}
}

##</code><code>##

use strict;
use warnings;

my @stack = @ARGV;
while (my $path = shift @stack) {
	my @dir_entries = glob("$path/*");
	foreach my $entry (@dir_entries) {
		print $entry, "\n" if -f $entry;
		push @stack, $entry if -d $entry;
	}
}

##</code><code>##

use strict;
use warnings;

my @stack = @ARGV;
while (my $entry = shift @stack) {
	print $entry, "\n" and next if -f $entry;
	push @stack, glob("$entry/*");
}

##</code><code>##

use strict;
use warnings;

my @stack = @ARGV;
while (my $entry = shift @stack) {
	print $entry, "\n" and next if -f $entry;
	unshift @stack, glob("$entry/*");
}