How to get WordPress post featured image url

Solution for : How to get WordPress post featured image url?

Below the simple code. It works for me.

 if (has_post_thumbnail( $post->ID ) ){
     $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'single-post-thumbnail' );
  $imageurl= $image[0]; //image url
 }