Cfrgtkky

I'm trying to make a UI, and I want objects to inherit properties. The way I do this is I have a templated class Widget which takes a variable amount of types that it inherits from (see code below).

However, when I try to make a class that inherits from Widget<Resizeable> I get an error: The default constructor of Widget<Resizeable> is deleted.

Could someone explain why this happens? Widget and Resizeable are both abstract, so why is the constructor being called?

Widget:

template<typename... B>

class Widget : public B...

{

public:

  virtual void Move(Vector position) = 0;

  virtual void Show(bool show) = 0;



  template<typename T>

  bool HasBehavior()

  {

    return std::is_base_of<T, std::remove_reference<decltype(*this)>::type>::value;

  }

protected:

  // protected members

};

Resizeable:

class Resizeble

{

  public:

    virtual void Resize(Vector size) = 0;



  Vector Size() const noexcept

  {

    return size_;

  }

  protected:

    Vector size_;

};

Rectangle:

class Rectangle : public Widget<Resizeble>

{

  public:

    Rectangle(Vector position, Vector size, Color color) : color_(color)

    {



    }

  private:

    Color color_;

};

SOLUTION:

Implement constructors for all base classes, and use virtual inheritance so that the most derived class (in this case, Rectangle) can call the constructors of all parent classes.