Getting Page/Post ID,Title,Slug,Object

Getting Page/Post ID,Title,Slug,Object

 <?php  
  $post_obj = $wp_query->get_queried_object();  
  $post_ID = $post_obj->ID;  
  $post_title = $post_obj->post_title;  
  $post_slug = $post_obj->post_name;  
 ?>  

(or)

 <?php  
 global $wpdb;  
 $id= $post->ID;  
 $postparent=$post->post_parent;  
 echo $id;  
 ?>  

(or)

 <?php  
 ob_start();  
 $id=the_ID();  
 $id=ob_get_contents();  
 ob_end_clean();  
 echo $id;  
 ?>