How to add a register & profile button

Hi,

I would like my blog to display a button for registering to my site, and once logged in a button for viewing their profile so users can update their password etc..

I’ve used this code in my functions.php to display the Log In & Log out function in my menu bar is there a similar sort of code for a Register button aswell as a profile button?

add_filter('wp_nav_menu_items', 'add_login_logout_link', 10, 2);
function add_login_logout_link($items, $args) {
        ob_start();
        wp_loginout('index.php');
        $loginoutlink = ob_get_contents();
        ob_end_clean();
        $items .= '<li>'. $loginoutlink .'</li>';
    return $items;
}

P.s the Profile button would need to be for logged in users only.