Hiding Posts in One Category

[realwx]

I can't get this plugin working. The main object of this plugin is to block guests from viewing any post in a set category via plugin file. I've set category number as 1. This is my first plugin, so don't yell at me!

PHP Code:

<?php
/*
Plugin Name: Bar Guests
Version: 1.0
....blah blah blah blah...
*/

$my_cat = "1";

function applysubbyposts($the_posts) {
 global $wpdb;
 if(!is_user_logged_in()) {
  foreach($the_posts as $key => $post) {
   $thiscat = $wpdb->get_var("SELECT category_id FROM post2cat WHERE post_id='$post->ID'");
   if(floatval($thiscat) == floatval($my_cat)) unset($the_posts[$key]);
  }
 }
 return $the_posts;
}
add_filter("the_posts", "applysubbyposts");
?>