Var.$logged defined in global.php, not picked up by index.php

Question

I was attempting to follow along with the tutorial at the youtube chanel

Helping Develop

when I came across a few issues. The first being his logout code in tutorial #5 doesn't work anymore due to the changed

    if(session_is_registered()  

I think I have replaced that properly with

    if( isset($_SESSION[$username])){

But now I am getting an error that says "Notice: Undefined variable: logged in C:\xampp\htdocs\membership\index.php on line 2"

When I check line 2 of index it shows that i am including global.php first

    <?php include_once('scripts/global.php');
     if($logged==1){
    header("Location:home.php");
        exit();
    }
    ?>

So then I check global.php which has $logged=1 so it should be defined...unless I am missing something. I am really trying to learn more here, so any help would be appreciated in explaining what is wrong, and why.... Thank you.

    <?php
    session_start();
    include_once('scripts/connect.php');

     //checking if the sessions are set
    if(isset($_SESSION['username'])){
               $session_username=$_SESSION['username'];
               $session_pass=$_SESSION['pass'];
               $session_id=$_SESSION['id'];

               //checking the member data
               $query=mysql_query("SELECT * FROM members WHERE
     id='id' AND password='pass' LIMIT 1")or die("Could not check member");
               $count_count=mysql_num_rows($query);
               if(count_count>0){
                //logged in stuff here
                $logged=1;

               }else{
                   header('Location:logout.php');
                   exit();
               }

               }elseif(isset($_COOKIE['id_cookie'])){
                $session_id=$_COOKIE['id_cookie'];
                $session_pass=$_COOKIE['pass_cookie'];

                //checking the member data
               $query=mysql_query("SELECT * FROM members WHERE    
    id='$session_id' AND password='$session_pass' LIMIT 1")or die("Could not check member");
               $count_count=mysql_num_rows($query);
               if(count_count>0){
                    while($row=mysql_fetch_array($query)){


    $session_username=$row['username'];
                    }
                   //create sessions
                   $_SESSION['username']=$session_username;
                   $_SESSION['id']=$session_id;
                   $_SESSION['pass']=$session_pass;

                //logged in stuff here
                    $logged=1;

               }else{
                   header('Location:logout.php');
                   exit();
                   }
               }



    ?>

Answer 1

$logged is set inside a conditional, so trace back through to understand how you might not hit a random redirect (reminds me of the crazy "goto" days which I through we progressed past) and end up with $logged not being set. Or initialize $logged at the beginning of the included script.