I must possess a specific divider after my posts.

I've 3 partitioning -> divider1,divider2,divider3

Basicly i'd like to allow them to loop, so after publish 1 i recieve divider1, publish 2-> divider2, post3->divider3, publish 4 ->divider1 etc...

This really is my code:

<div class="post">
              <div class="post-title">
                  <h2><a href="<?php the_permalink() ?>" rel="bookmark"
                         title="Permanent Link to  <?php the_title_attribute(); ?>">
                      <?php the_title(); ?>
                  </a></h2>
              </div>
              <div class="post-date">
                  <?php the_time('j-n-Y') ?><br/>
              </div>

              <div class="entry">
                  <?php the_excerpt();?>
              </div>
              <div class="meta">
                  <span class="post-cat"><?php the_category(',') ?></span>
                  <span class="post-comments"> <?php comments_popup_link('No Comments', '1 Comment', '% Comments'); ?></span>
              </div>
              <div class="divider1"></div>
          </div>

therefore the class should loop from divider1 to divider2 to divider3 to divider1 and on looping, can anybody assist me to?

Create a counter and appearance its modulus to cycle one to three (really we'll use to two)

// Start counter at 0
$counter = 0;
// This is your loop
foreach ($posts as $post) {

  // Now a switch will determine which divider to use.
  // We'll select class divider1 divider2 or divider3 based 
  // on the current counter position. This will keep looping no
  // matter how many posts you have
  switch ($counter % 3) {
    case 0: // output divider 1
      $divider_class = 'divider1';
      break;
    case 1: // output divider 2
      $divider_class = 'divider2';
      break;
    case 2: // output divider 3
      $divider_class = 'divider3';
      break;
  }

  // All your HTML is output here...
  // Skipping most of it for brevity, but the important part is the divider...
  <div class="<?php echo $divider_class;?>"></div>

  // EDIT Forgot the important step of incrementing the counter...
  $counter++;

// Don't forget to close your loop
}

You will find different ways you could do this this. For instance, with no switch you are able to set the divider class directly using the modulus:

// Alternate method - no switch and less typing but less flexible
$divider_class = "divider" . ($counter % 3);

<div class="<?php echo $divider_class;?>">