Find oldest post — WordPress - php

Question

Thanks to some answers on here, I've managed to distinguish my posts into the latest post and all the rest. However, it needs to be the oldest post. Here is my current loop:
<?php if (have_posts()) : ?>
<?php $post = $posts[0]; $c=0;?>
<?php while (have_posts()) : the_post(); ?>
<!-- first post -->
<?php $c++;
if( $c == 1) :?>
<div class="container">
<div class="inner_box">
<ul>
<div class="title">
<a href="<?php the_permalink();?>">
<?php the_title(); ?>
</div>
<?php the_content(); ?>
</a>
</ul>
<div class="down">a</div>
</div>
</div>
<?php else :?>
<!-- second post -->
<div class="container">
<div class="inner_box">
<ul>
<div class="title">
<a href="<?php the_permalink();?>">
<?php the_title(); ?>
</div>
<?php the_content(); ?>
</a>
</ul>
<div class="up">b</div>
</div>
</div>
<?php endif; ?>`
I saw somewhere that you can use a while loop to target the last post from a post.length. However, I am unsure how to implement this.

Answer 1

Yes, you're right. Use count.
Suppose the total posts is 5 for $total_posts = count($posts);.
You'll have to check your $counter for total - 1 as the array is $posts[0], $posts[1], $posts[2], $posts[3], $posts[4].
<?php
if ( have_posts() ) :
$counter = 0;
$total_posts = count($posts) - 1;
while ( have_posts() ) :
the_post();
if( $counter == $total_posts ) {
?>
<div class="container"><?php // CUSTOM CODE FOR LAST ARTICLE ?></div>
<?php
} else {
?>
<div class="container"><?php // CUSTOM CODE FOR THE REST OF ARTICLES ?></div>
<?php
}
$counter++;
endwhile;
endif;
Note that you only need to open <?php and close ?> when changing from PHP to HTML, using them at every line is very confusing.