Protected Page without touching database [how to display username] [duplicate]

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• 
  SESSION['username'] is not set
  
  3 answers
  
  

I was desired to make some protected pages for my website. When i was searching hard to get this solution, i got it here at http://www.w3schools.in/php/php-login-without-using-database/.

As i have seen, the username required to be set manually here at the fourth line of the code below.(i don't mind to set it manually as i only need a few protected pages). The code below i copied from url above login.php.

    /* Check Login form submitted */    
    if(isset($_POST['Submit'])){
        /* Define username and associated password array */
        $logins = array('Alex' => '123456','username1' => 'password1','username2' => 'password2');

        /* Check and assign submitted Username and Password to new variable */
        $Username = isset($_POST['Username']) ? $_POST['Username'] : '';
        $Password = isset($_POST['Password']) ? $_POST['Password'] : '';

        /* Check Username and Password existence in defined array */        
        if (isset($logins[$Username]) && $logins[$Username] == $Password){
            /* Success: Set session variables and redirect to Protected page  */
            $_SESSION['UserData']['Username']=$logins[$Username];
            header("location:index.php");
            exit;
        } else {
            /*Unsuccessful attempt: Set error message */
            $msg="<span style='color:red'>Invalid Login Details</span>";
        }
    }
?>

I would like to ask that, what php code should i put in order to display a username after logged in successfully? Any suggestion? Appreciate your help! I'm still new in php programming.