Help making a set of C++ Classes

Projects Programming
21

Getting rid of it means you'll no longer be able to reference all the different button type classes polymorphically via a pointer to the base class.

22

It's getting kind of complicated. But, this code will fail at compile time if the wrong flavor of read() is called statically on a child class object (because the wrong variants are private:).

And it will fail the run-time assert() if the wrong flavor of read() is called polymorphically via a Button * pointer.

class Button {
  public:
    virtual byte read() = 0;
    virtual byte read(byte a) = 0;
    virtual byte read(byte a, byte b) = 0;
};

class SingleButton : public Button {
  private:
    byte read(byte a) override {
      assert(false && "Illegal polymorphic call to 1-arg read()"); 
      return 0;
    }
    byte read(byte a, byte b) override {
      assert(false && "Illegal polymorphic call to 2-arg read()"); 
      return 0;
    }

  public:
    byte read() override {
      // Determine Button State Here
      return buttonState;
    }
};


class ButtonArray : public Button {
  private:
    byte read() override {
      assert(false && "Illegal polymorphic call to 0-arg read()"); 
      return 0;
    }
    byte read(byte a, byte b) override {
      assert(false && "Illegal polymorphic call to 2-arg read()"); 
      return 0;
    }

  public:
    byte read(byte a) override {
      // Determine Button State Here
      return buttonState;
    }
};

class ButtonMatrix : public Button {
  private:
    byte read() override {
      assert(false && "Illegal polymorphic call to 0-arg read()"); 
      return 0;
    }
    byte read(byte a) override {
      assert(false && "Illegal polymorphic call to 1-arg read()"); 
      return 0;
    }

  public:
    byte read(byte a, byte b) override {
      // Determine Button State Here
      return buttonState;
    }
};
23

It seems like you're looking for something like this.

It's totally non-blocking.

Oh, and you can have as many as you like.