If you encounter a problem with form validation, please indicate the problem (PHP validation)-PHP Chinese Network Q&A

I want to know what is wrong with the form in my code.

<?php

if(isset($_POST['submit'])) {
  $arrayName = array("TeacherA", "TeacherB", "TeacherC" , "TeacherD", "TeacherE");

  $minimum = 5;
  $maximum = 10;

  $name = $_POST['yourName'];
  $email = $_POST['yourEmail'];

  if(strlen($name) < $minimum) {
    echo "Your name should be longer than 5 characters";
  } 
  
  if(strlen($name) > $maximum) {
    echo "Your name should not be longer than 10 characters";
  } 
  
  if(!in_array($name,$arrayName)){
    echo "Please do register with us before you can login";
  } else {
    echo "Welcome!";
  }
}
?>

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Blank</title>
</head>
<body>
  <form action="form.php" method="post">
    <label>Your Name:    </label>
    <input type="text" name="yourName"> <br>

    <label for="">Your E mail:</label>
    <input type="email" name="yourEmail" id=""><br>
    
    <!-- <textarea name="yourMessage" id="" cols="30" rows="10"></textarea><br> -->
    <input type="submit" name="submit" value="submit">
  </form>
</body>
</html>

I ran the code locally, but couldn't get the results I wanted.

The result I want is that if I do not enter a name in the "Your Name" field, the result should be displayed:

Please register before logging in

$maximum) { echo "Your name should be less than 10 characters"; } else { if (in_array($name, $arrayName)) { echo "Welcome!"; } else { echo "Your login is not correct"; } } } } } ?>