Check child/parent categories if exists

i am serching a WP function that controls is there any child category/ies of current category (in category.php outside of the loop) and if there is, just add link list for that category/ies to page, otherwise (there is no child category for current) list all post(s) in this category.
Thanks in advance…

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You can get the current posts category outside the loop by using the get_the_category function.

When you have the actual category ( however you got it) you can use get_categories, specifically the ‘child_of’ parameter and pass it the parent cat ID.

Also have a look at wp_list_catagories,
where you can do something simple like the following to grab the children.

 <?php wp_list_categories('orderby=id&show_count=1&use_desc_for_title=0&child_of=8'); ?>

You would probably do an “if” statement to get the children if they exist and if not just show the category.