how to create custom post type in wordpress without plugin code example

Example: wp+create custom post type and category

add_action( 'init', 'create_news' );
function create_news ()
{      
    register_post_type( 'ecommerces',
                array(
                'labels'        => array(
                'name'          => __( 'Ecommerces' ),
                'singular_name' => __( 'Ecommerce' )
                ),
                'public'   => true,
                'supports' => array ('title', 'editor', 'thumbnail')
                )
                );

    register_taxonomy(
                'ecommerce_cat',
                'ecommerces',
                array(
                'labels' => array(
                'name' => 'Ecommerce Categories',
                'add_new_item' => 'Add New Ecommerce Category',
                'new_item_name' => "New Ecommerce Category"
                ),
                'show_ui' => true,
                'show_tagcloud' => false,
                'hierarchical' => true,
                'hasArchive' => true
                )
                );

    }

    if ( function_exists( 'add_theme_support' ) ) {
    add_theme_support( 'post-thumbnails' );
    set_post_thumbnail_size( 100, 100, true ); 
}

    ?>