How to add login and registration links in the header of a WordPress site?

Question

WordPress

I need that in the header of the site, when a person is not authorized, links to login / registration are displayed, and when authorized - the user's nickname and a link to logout.

Answer 1

if ( is_user_logged_in() ) {
  # пользователь авторизован
} else {
  # пользователь НЕ авторизован
}