Need to know custom code to display random and most viewed posts in wordpress posts and pages

A standard WordPress install doesn’t keep track of visits to pages/posts. So without a plugin there’s no way to know which posts/pages are visited most often. As to finding random posts that’s as simple as:

$args = array(
  'post_type' => array( 'post', 'page', 'my-custom-post-type' )
  'orderby' => 'rand',
  );
$query = new WP_Query ($args);