The following is a functional index file (index.php), which displays the contents (and only the contents) of each post, according to the conditions used to prepare The Loop. This example demonstrates how little is actually necessary for the functioning of The Loop.
<?php
get_header();
if (have_posts()) :
while (have_posts()) :
the_post();
the_content();
endwhile;
endif;
get_sidebar();
get_footer();
?>