I want to make a modulo condition in my ACF Repeater field.

In a while loop, I want my code different if $j is odd or even.

My code:

<div class="container grow mt-5">
<h1 class="text-center">Expositions</h1>

<?php
    $j = 1;
    if( have_rows('expos') ):
        while ( have_rows('expos') ) : the_row();
        $titre= get_sub_field('titre');
        $img = get_sub_field('image');
        $contenu = get_sub_field('contenu');

        if ($j%2 == 1) {
        echo '

         <div class="row mt-5">
            <div class="col-4">
                <img class="thumbnail" src="'.echo esc_url($img['url']);.'" alt="'.esc_attr($img['alt']);.'" />    
            </div>
            <div class="col-8">
                <h2 class="text-center">'.$titre.'</h2>
                <p>'.$contenu.'</p>
            </div>
            </div>'
    } else {
        echo '
         <div class="row mt-5">
            <div class="col-8">
                <h2 class="text-center">'.$titre.'</h2>
                <p>'.$contenu.'</p>
            </div>
            <div class="col-4">
                <img class="thumbnail" src="'.echo esc_url($img['url']);.'" alt="'.esc_attr($img['alt']);.'" />    
            </div>


            </div>'
    };


    $j++;
    endwhile;
    else :
        echo '<p class="text-center">No content !</p>';
    endif;
    ?>

</div>

It doesn’t work.

Where is my error ?