g

<?php
session_start();
  if(isset($_POST)){
    //make connection
    $servername = "localhost";
    $username = "root";
    $password = "";
    $dbname = "exam";

    // Create connection
    $conn = new mysqli($servername, $username, $password, $dbname);
    // Check connection
    if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
    }
    if((isset($_POST['username']) && !empty($_POST['username'])) && (isset($_POST['password']) && !empty($_POST['password']))){
    $username = trim(htmlspecialchars($_POST['username']));
    $password = md5(trim($_POST['password']));
    $query = "SELECT * FROM users WHERE username = '$username' AND password = '$password'";
    $row = $conn->query($query);
    if($fetch = $row->num_rows == 1){
      $guka = $row->fetch_assoc();

      $_SESSION['username'] =  $guka['username'];
      $_SESSION['password'] =  $guka['password'];

      print_r($_SESSION);
    }else{
      echo "incorrect password";
    }

  }
$conn->close();
  }
?>
<!DOCTYPE html>
<html lang="en" dir="ltr">
  <head>
    <meta charset="utf-8">
    <title></title>
  </head>
  <body>
    <form class="" method="post">
      <input type="text" name="username" placeholder="username">
      <input type="password" name="password" placeholder="password">
      <input type="submit" name="" value="submit">
    </form>
    <?php
    if(isset($_SESSION)){

      echo $_SESSION['username'];
    }

     ?>
  </body>
</html>