Show a list of wordpress registered custom post types

show_registered_post_types.php

function show_registered_post_types(){

   $args=array(
        'public'                => true,
        'exclude_from_search'   => false,
        '_builtin'              => false
    ); 

    $output = 'names'; // names or objects, note names is the default
    $operator = 'and'; // 'and' or 'or'
    $post_types = get_post_types($args,$output,$operator);

    $posttypes_array = array();

    foreach ($post_types  as $post_type ) {
        $posttypes_array[] = $post_type;
    }

    var_dump($posttypes_array);
}

add_action( 'wp_head', 'show_registered_post_types' );