<?php
 ShowCategories(0);
function ShowCategories($parent_category) {
$categories = get_categories(array('parent' => $parent_category, 'hide_empty' => 0));
foreach ($categories as $category) { ?>
<ul><li><?php echo $category->cat_name;
$args = array("cat"=>$category->term_id);
$the_query = new WP_Query( $args );
if ( $the_query->have_posts() ) { ?>
<ul>
<?php while ( $the_query->have_posts() ) {
$the_query->the_post(); ?>
<li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
<?php } ?>
</ul>
<?php wp_reset_postdata();
} else {
// yazi yok
} ?>
<?php ShowCategories($category->cat_ID); ?></li></ul>
<?php
}
} ?>