Code to add social icons below WordPress post content using filter

wp-social-icons.php

/**
 * Add social icons below post title using WordPress filter
 * * How to use: You can add following code in functions.php in WordPress theme.
 */

// Use WordPress filter to add custom content below WordPress post
add_filter('the_content', 'tc_social_icons_callback');
function tc_social_icons_callback($content)
{
	// Get current page URL 
	$post_url = urlencode(get_permalink());

	// Get current page title
	$post_title = str_replace(' ', '%20', get_the_title());
	$blog_title = get_bloginfo('name');

	// Create sharing URL
	$twitterURL = 'https://twitter.com/intent/tweet?text=' . $post_title . '&url=' . $post_url;
	$facebookURL = 'https://www.facebook.com/sharer/sharer.php?u=' . $post_url;
	$linkedInURL = 'https://www.linkedin.com/shareArticle?mini=true&url=' . $post_url . '&title=' . $post_title;
	$pinterestURL = 'http://pinterest.com/pin/create/link/?url=' . $post_url . '&description=' . $post_title;

	$share_buttons = '
        <div id="tc-social-share">
			<a target="_blank" href="'.$facebookURL.'" class="facebook">Facebook</a>
			<a target="_blank" href="'.$twitterURL.'" class="facebook">Twitter</a>
			<a target="_blank" href="'.$linkedInURL.'" class="facebook">LinkedIn</a>
			<a target="_blank" href="'.$pinterestURL.'" class="facebook">Pinterest</a>
        </div>';

	// append share icons after content
	return $content . $share_buttons;
}