Code snippet to show recent posts from category in wordpress. For more information on how to use it properly and other alternatives please refer to : http://wpvkp.com/show-latest-posts-from-category/

function.php

<?php

function cust_post() {
$check = new WP_Query( array( 'category_name' => 'nameit', 'posts_per_page' => 5 ) ); 

if ( $check->have_posts() ) {
            // To enable the theme's default style for list elements
	$string .= '<ul class="cust_post widget_recent_entries">';
            // Checks if the post is present in the category
	while ( $check->have_posts() ) {
		$check->the_post();
            // Condition to check if the featured image is available
			if ( has_post_thumbnail() ) {
			$string .= '<li>';
			$string .= '<a rel="nofollow" href="' . get_the_permalink() .'" target="_blank" rel="bookmark">' . get_the_title() .'</a></li>';
			}
			}
	} else {
	// If no post is present in the category
}
$string .= '</ul>';

return $string;

wp_reset_postdata();
}

add_shortcode('custp', 'cust_post');

add_filter('widget_text', 'do_shortcode');


?>