get if user is already logged in php wordpress code example

Example 1: if user logged in wordpress

if ( is_user_logged_in() ) {
   // your code for logged in user 
} else {
   // your code for logged out user 
}

Example 2: php redirect if not logged in

if(!isset($_SESSION['login'])){ //if login in session is not set
    header("Location: http://www.example.com/login.php");
}