# Print all files in a directory
sub print_files {
    my $dir = 'd:/code';
    opendir DIR, $dir or die $!;
    my @files = readdir DIR;
    chdir $dir; # Use chdir or -f will not work, since -f need absolutely path
    foreach my $file (@files) {
        if (-f $file) {
            print "$file\n";
        }
    }
    closedir DIR;
}

print_files();