$loop->have_posts() code example

Example 1: if (have_posts()): while(have_post()):the_post();

<?php 
if ( have_posts() ) {
	while ( have_posts() ) {
		the_post(); 
		//
		// Post Content here
		//
	} // end while
} // end if
?>

Example 2: wordpress loop first two post

<div class="col-lg-12">
    <div class="row">

            <?php if ( have_posts() ) : ?>
            <?php if ( in_category( 'Featured' ) ) : /* Start the Featured Loop */ ?>

                <?php while( have_posts() ) : the_post(); ?>

                <?php if( $wp_query->current_post == 0 ) { 
                //open wide column wrapper div// ?>
                <?php } ?>

                <?php if( $wp_query->current_post <= 1 ) { 
                get_template_part( 'content', 'featured' );
                //insert large post// ?>
                <?php } ?>

                <?php if( $wp_query->current_post == 1 || $wp_query->current_post <= 1 && $wp_query->current_post == $wp_query->post_count-1 ) { 
                //close wide column div// ?>
                <?php } ?>

                <?php if( $wp_query->current_post == 2 || $wp_query->current_post <= 1 && $wp_query->current_post == $wp_query->post_count-1 ) { 
                //open narrow column wrapper div// ?>
                <?php } ?>

                <?php if( $wp_query->current_post >= 2 ) { 
                get_template_part( 'content', 'featuredside' );
                //insert small post//?>
                <?php } ?>

                <?php if( $wp_query->current_post == 4 || $wp_query->current_post == $wp_query->post_count-1 ) { 
                //close narrow column div// ?>
                <?php } ?>

                <?php endwhile; ?>

                    <?php endif; ?>

                <?php endif; ?>

    </div> <!--/.row-->
</div> <!--/.col-lg-12-->