if(isset($_GET['plus'])){
   $_SESSION['product_'.$_GET['plus']]+=1;
   if($_SESSION['product_'.$_GET['plus']] < 1){
   header('Location: checkout.php');
   }else{
   header('Location: checkout.php');
    }
}


 if(isset($_GET['remove'])){
   $_SESSION['product_'.$_GET['remove']]--;
   if($_SESSION['product_'.$_GET['remove']] < 1){
   header('Location: checkout.php');
   }else{
   header('Location: checkout.php');
    }

}

 if(isset($_GET['delete'])){
    $_SESSION['product_'.$_GET['delete']] = '0';
    header('Location: checkout.php');
}

$btn_add='<a class="btn btn-success" href="cart.php?plus='.$id.'"><i class="fa fa-plus fa-lg" aria-hidden="true" add_btn></i></a>';

$btn_remove = '<a class="btn btn-warning" href="cart.php?remove='.$id.'"><i class="fa fa-minus fa-lg" aria-hidden="true" remove_btn></i></a>';

$btn_delete='<a class="btn btn-default delete_btn" href="cart.php?delete='.$id.'"><i class="fa fa-times fa-lg" aria-hidden="true"></i></a>';