如何在wordpress的每三个帖子上添加css类？

Question

I want to add a css class to every third post display on page. I have tried this code given below:

 <?php if (have_posts()) : ?>
 <?php $c = 0;
     while (have_posts()) : the_post(); $c++;
        if( $c == 3) {
            $style = 'third';
            $c = 0;
        }
        else $style='';
     ?>
     <div <?php post_class($style) ?> id="post-<?php the_ID(); ?>">

Answer 1

try to change

 while (have_posts()) : the_post(); $c++;
 if( $c == 3) {
        $style = 'third';
        $c = 0;
    }
    else $style='';

with

 while (have_posts()) : the_post();
      if( $c % 3 == 0 )
         $style = 'third';
       else
         $style = '';

and make increment of varible $c++; before the while loop ends

I feel

<?php post_class($style) ?> id="post-<?php the_ID(); ?>">

is working, if not than change it to

<?php class = "<?php $style; ?>" id="post-<?php the_ID(); ?>">