Uncaught TypeError: mysqli_connect(): Argument #5 ($port) must be of type ?int, [closed]

Error:

Fatal error: Uncaught TypeError: mysqli_connect(): Argument #5 ($port)
must be of type ?int, string given in
C:xampphtdocsproj-phpconnections.php:10 Stack trace: #0
C:xampphtdocsproj-phpconnections.php(10):
mysqli_connect(‘localhost’, ‘root’, ’email;’, ”,
‘login_register_…’) #1 C:xampphtdocsproj-phpregister.php(6):
include(‘C:xampphtdocs…’) #2 {main} thrown in
C:xampphtdocsproj-phpconnections.php on line 10

enter image description here

php code:
enter image description here