Doubt

class Widget {
private:
  unsigned int h,w;
  bool visible;
public:
  virtual void setStandardSize() =0;

  Widget(unsigned int height=0, unsigned int width=0, bool vis =true):
    h(height), w(width), visible(vis) {}

  virtual ~Widget() =default;

  void setHeight(unsigned int height) {h=height;}
  void setWidth(unsigned int width) {w=width;}
};

#include<string>

class AbstractButton: public Widget {
private:
  std::string label;
public:
  AbstractButton(unsigned int height=0, unsigned int width=0, bool vis =true,
         const std::string& l=""): Widget(height,width,vis), label(l) {}

  std::string getLabel() const {return label;}
};

class PushButton: public AbstractButton {
public:
  static const unsigned int standardHeight = 80;
  static const unsigned int standardWidth = 20;

  void setStandardSize() override {
    setHeight(standardHeight); setWidth(standardWidth);
  }

  PushButton(unsigned int height=standardHeight, unsigned int width= standardWidth,
         bool vis =true, const std::string& l=""): AbstractButton(height,width,vis,l) {}
};

class CheckBox: public AbstractButton {
private:
  bool checked;
public:
  static const unsigned int standardHeight = 5;
  static const unsigned int standardWidth = 5;

  void setStandardSize() override {
    setHeight(standardHeight); setWidth(standardWidth);
  }

  CheckBox(unsigned int height=standardHeight, unsigned int width= standardWidth,
       const std::string& l="", bool check=false):
    AbstractButton(height,width,true,l), checked(check) {}

  bool isChecked() const {return checked;}
};

#include<vector>
#include<list>

class Gui {
private:
  std::vector<const Widget*> NoButtons;
  std::list<const AbstractButton*> Buttons;
public:
  void insert(Widget* pw) {
    if(pw == nullptr) throw std::string("NoInsert");
    if(dynamic_cast<AbstractButton*>(pw) != nullptr)
      Buttons.push_back(static_cast<AbstractButton*>(pw));
    else NoButtons.push_back(pw);
  }

  void insert(unsigned int pos, PushButton& pb) {
    if(pos > Buttons.size()) throw std::string("NoInsert");
    auto it = Buttons.begin();
    for( ; pos>0; pos--, it++);
    Buttons.insert(it, &pb);
  }

  std::vector<AbstractButton*> removeUnchecked() {
    std::vector<AbstractButton*> v;
    CheckBox* p;
    for(auto it=Buttons.begin(); it!=Buttons.end(); ++it) {
      p=const_cast<CheckBox*>(dynamic_cast<const CheckBox*>(*it));
      if(p && !(p->isChecked())) {
    v.push_back(p);
    it=Buttons.erase(it); --it;
      }
    }
    return v;
  }

  void setStandardPushButton() {
    for(auto it = Buttons.begin(); it != Buttons.end(); ++it)
      if(dynamic_cast<const PushButton*>(*it) != nullptr && !((*it)->getLabel().empty()))
     (const_cast<AbstractButton*>(*it))->setStandardSize();
  }
};