{if $cat.child}
有子类显示父类
{category pid=$cat.pid return=c}
{$c.name}
{/category}
<hr>
显示子类
{loop $related $c}
{$c.name}
{/loop}
{else}
没有子类
{loop $related $c}
{$c.name}
{/loop}
{/if}