include_once, relative path in php

Question

I have 3 files: home, failed_attempt, login.

The file home and failed_attempt all refer to login file.

The annoying thing is that they throw a mistake saying

Answer 1

The other guys have answered your question correctly, however I thought I'd contribute something else: autoloaders.

Autoloaders allow you to define a function that will automatically include certain files, when you attempt to use a class.

The documentation is here and can explain it better than I can: http://php.net/manual/en/language.oop5.autoload.php

Would really recommend using them, will save you time and is better practice.