Is it mandatory to have an initializer with the required modifier without protocol implementation?

In iOS (Swift), an initializer with the required modifier is mandatory in classes that can be subclassed if you want all subclasses to implement this initializer. However, if a class does not conform to protocols that require a specific initializer, then having a required initializer is not necessary.

That is, a required initializer is needed to ensure that all subclasses implement this initializer, especially when working with inheritance and protocols. If protocols do not require an initializer, and you do not plan to use inheritance, then you can omit the required keyword.