Gra: Zgadnij liczbę

<?php
session_start();

if (isset($_GET['reset'])) {
  unset($_SESSION['number']);
  header("Location: guess.php");
  exit;
}

if (!isset($_SESSION['number'])) {
  $_SESSION['number'] = rand(1,50);
}

$msg = "";
if (isset($_POST['guess'])) {
  $guess = (int)$_POST['guess'];
  if ($guess < $_SESSION['number']) $msg = "Więcej!";
  elseif ($guess > $_SESSION['number']) $msg = "Mniej!";
  else $msg = "Gratulacje! Zgadłeś liczbę ".$_SESSION['number'];
}
?>

<form method="post">
  Twoja liczba (1-50): <input type="number" name="guess" required>
  <input type="submit" value="Sprawdź">
</form>

<?php if($msg) echo "<p>$msg</p>"; ?>