wordpress add post class code example

Example 1: what is post_class()

/*    Use an array to add multiple classes in post_class() function:  */
<?php
$classes = array(
    'class1',
    'class2',
    'class3',
);
?>
 
<div id="post-<?php the_ID(); ?>" <?php post_class( $classes ); ?>>

Example 2: what is post_class()

/*  A simple way to add multiple classes to the post_class defaults, is to just write them as a string argument:  */

<div <?php post_class( 'class1 class2 class3' ); ?>>