title: Creating and adding to a session
body: <p>I am creating a shopping cart and having some trouble adding the first item to it. The shopping cart code is below:</p>
  
  <pre><code>switch($action) { //decide what to do 
  
      case "add":
  
          $_SESSION['cart'][$Item_ID]++; //add one to the quantity of the product with id $product_id 
      break;
  
      case "remove":
          $_SESSION['cart'][$Item_ID]--; //remove one from the quantity of the product with id $product_id 
          if($_SESSION['cart'][$Item_ID] == 0) unset($_SESSION['cart'][$Item_ID]); //if the quantity is zero, remove it completely (using the 'unset' function) - otherwise is will show zero, then -1, -2 etc when the user keeps removing items. 
      break;
  
      case "empty":
          unset($_SESSION['cart'][$Item_ID]); //unset the whole cart, i.e. empty the cart. 
      break;
  
      case "nothing":
      break;
  }
  </code></pre>
  
  <p>When I add an item for the first time (the first one added to the basket) it gives me these errors</p>
  
  <pre><code>Notice: Undefined index: cart in H:\STUDENT\S0190204\GGJ\Basket.php on line 59 Notice: Undefined index: 1 in H:\STUDENT\S0190204\GGJ\Basket.php on line 59
  </code></pre>