Perl: Modify certain line number in text-file

Just wrote up a small pseudocode for a previous post here.
open (IF, "infile.txt");
open (OF, "outfile.txt");
  while (my $line = <IF>) {
    $count++;
    if ($count == 10) {
      # Modify
      print OF "somethingelse\r\n";
    } else {
      # Don't modify
      print OF $line;
    }
  }
close(OF);
close(IF);