Wordpress count view and popular posts without using plugins

<?php

/* Visit Counter For WordPress by Talkofweb.com */
function getPostViews($postID){
$count_key = 'post_views_count';
$count = get_post_meta($postID, $count_key, true);
if($count==''){
delete_post_meta($postID, $count_key);
add_post_meta($postID, $count_key, '0');
return "0 View";
}
return $count.' Views';
}
function setPostViews($postID) {
$count_key = 'post_views_count';
$count = get_post_meta($postID, $count_key, true);
if($count==''){
$count = 0;
delete_post_meta($postID, $count_key);
add_post_meta($postID, $count_key, '0');
}else{
$count++;
update_post_meta($postID, $count_key, $count);
}
}


?>

paste this after the_content();. The below code will count for every visit using the setPostViews(); function.

<?php setPostViews(get_the_ID());?>


<?php echo getPostViews(get_the_ID());;?>


Getting the most popular WordPress post Loop using the Visits Counter:


  <h3>Popular Stuff:</h3>
    <?php
$popularpost = new WP_Query( array( 'posts_per_page' => 4, 'meta_key' => 'post_views_count', 'orderby' => 'meta_value_num', 'order' => 'DESC'  ) );
while ( $popularpost->have_posts() ) : $popularpost->the_post();?>
<li>
<a href="<?php the_permalink() ?>" title="<?php the_title();?>"><h1><?php the_title();?></h1></a>
</li>
<?php endwhile; ?>
<?php wp_reset_query(); ?>