Delete a content type programmatically

Here is a real example of how a Content Type with "event" machine name is deleted.

  // If the content type is added as the feature (optional).
  module_disable(array('dennis_events'));
  drupal_uninstall_modules(array('dennis_events'));

  // Delete ALL Event nodes.
  $query = db_select('node', 'n');
  $query->fields('n', array('nid'));
  $query->condition('n.type', 'event');
  $nids = $query->execute()->fetchCol();
  if (!empty($nids)) {
    node_delete_multiple($nids);
  }
  
  // Delete the CT itself.
  node_type_delete('event');
  variable_del('node_preview_event');
  drupal_set_message('The content type "Event" has been deleted.');
  watchdog('node', 'Deleted content type "Event".', [], WATCHDOG_NOTICE);