How to automatically get the user's email adress

Sorry, i wanted to say “how to automatically get the Username of a registered user” and not the email adress.

Thanks again

See Special Mail Tags

None of those give you the Current logged in user.

Before you could add code to the file plugins/contact-form-7/modules/special-mail-tags.php I added this code:

add_filter( 'wpcf7_special_mail_tags', 'wpcf7_special_mail_tag_userdata', 10, 2 );

function wpcf7_special_mail_tag_userdata( $output, $name ) {

	// For backwards compat.
	$name = preg_replace( '/^wpcf7\./', '_', $name );

	global $current_user;

	if ( 'user_login' == $name )
		$output = $current_user->user_login;

	return $output;
}

But on 3.9 that file does not exist or at lease i can’t find it.
We need to know how or where to add this code now.