Promo Shortcode

// Promo Shortcode
function recent_post_shortcode($atts){
   extract(shortcode_atts(array(
      'posts' =>4,
   ), $atts));

   $return_string = ''; // wrapper will go here start
   query_posts(array('post_type'=>'frost_promo','posts_per_page'=>4,'order' => 'ASC','showposts' => $posts));
   if (have_posts()) :
      while (have_posts()) : the_post();
      $image = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'promo');

         $return_string .= '<div class="promo_option_promo text-center" style="width:270px;float:left;">
                            <img src="'.$image[0].'" alt="'.get_the_title().'" />
                            <h2 class="text-uppercase">'.get_the_title().'</h2>
                            <p>'.get_the_content().'</p>
                            </div>';
      endwhile;

        else: // if no post found the above then show here default data
        $return_string .='<div class="error-not-found text-center">Sorry, no portfolio entries for while.</div>'; // this is data end

   endif;
   $return_string .= '';  // wrapper will go here end
   wp_reset_query();
   return $return_string;
}

add_shortcode('recent-post','recent_post_shortcode');


// shortcode will be like this
<div class="row">
    <div class="container">
        <div class="col-md-12">
           <?php echo do_shortcode('[recent-post posts=4]');?>
        </div>
    </div>
</div>



// custom post
  // promo area how it works
    register_post_type( 'frost_promo',
    array(
      'labels' => array(
        'name' => __( 'Promos How It works' ),
        'singular_name' => __( 'Promo' ),
        'add_new'=>_('Add New Promo')
      ),
      'public' => true,
       'menu_icon'=> 'dashicons-camera',  /* For Dashicons Menu */
      'has_archive' => true,
      'rewrite'=> array( 'slug' => 'promo' ),
      'supports'=> array( 'title','thumbnail','editor' )

    )
  );