Question

I want to Constraint that the Derived Class must have a Default Constructor.
I am currently thinking it in a perverted way

template <typename Derived>
class Base{
  public:
    Base(){

    }
    virtual ~Base(){
      new Derived;
    }
};

Another idea comes to mind is to keep a pure virtual create() method with no arguments.

But is there any other way ? Other than these two.
I am thinking it in C++ way. But Is there any way to do this in PHP (I expect negetive answer LOL)

Answer 1

Yes, there’s a way in PHP LOL:

abstract class Base {
    public final function __construct() {
        $this->constructImpl();
    }
    abstract protected function constructImpl();
}

class Derived extends Base {
    protected function constructImpl() {
        /* implementation here */
    }
}

Basically, you just have to mark the constructor final.