重新加载页面时不显示输出

Question

I have created a small application which writes the contents of the $email variable into the file mailadressen.txt. If the file exists, the message "Email address already exists" (E-Mail-Adresse bereits vorhanden) appears. If I change the mail adress and reload the page then it doesn't output nothing. But if I reload it again with the new email address if displays the message "Email address already exists" again.

Can someone give me a tip why it doesn't output anything on the first reload but only on the second reload?

<?php
    $email = "[e-mail]";

    // open file and read & write
    $handle = fopen ("mailadressen.txt", "a+");

    while ( $inhalt = fgets ($handle, 4096 ))
    {
      $inhalt = trim ( $inhalt );
      echo "<li> |". $inhalt ."| </li>";
      if ( $inhalt == $email)
      {
        echo "E-Mail-Adresse bereits vorhanden";
        continue;
      }
    }

    fwrite($handle, $email);

    // new line
    fwrite($handle, "
");

    fclose($handle);
    ?>

Answer 1

Here's one solution based on my comment.

$email = "[e-mail]";

// open file and read & write
$handle = fopen ("mailadressen.txt", "a+");

while ( $inhalt = fgets ($handle, 4096 )){

  $inhalt = trim ( $inhalt );
  echo "<li> |". $inhalt ."| </li>";

  if ( $inhalt == $email){
    $email_exists = true;
    $msg = "E-Mail-Adresse bereits vorhanden";
    continue;
  }
}

//echo the message if email already exists
if(isset($email_exists) && $email_exists === true){
  echo $msg;
}
  else{
    //let's write only non existing email to the file
    fwrite($handle, $email);

    // new line
    fwrite($handle, "
");

    echo "Wrote new email: " . $email . " into the mailadressen.txt file.";
  }

fclose($handle);