open (MYOUTFILE, ">outfile.txt") or die "Can't create outfile: $!";

    # Other code

    print MYOUTFILE "$A,$B,n/a\n" if $i==0;
    print STDOUT "$A,$B,n/a\n" if $i==0;

    # Other code

  close MYOUTFILE;

##</code><code>##

   if ($i==0){
      print MYOUTFILE "$A,$B,n/a\n";
      print STDOUT "$A,$B,n/a\n";
    }