PHP compteur simple

<?php
$counterfile="conta.txt";
if (!file_exists($counterfile))
{
  $stack=1;
  $file=fopen($counterfile,"w+");
  fputs($file,$stack);
  fclose($file);  
} else {
  $file=fopen($counterfile,"r");
  $tot=fgets($file,20);
  $tot++;
  fclose($file);
  $file=fopen($counterfile,"w+");
  $tot=fputs($file,$tot);  
  fclose($file);
}
?>