c++ - Allocating an object of abstract class type when trying to create a SceneNode -

i have issue don't manage solve in c++.

i have class called scenenode. in class, there isn't virtual function , in private members, have vector of unique_ptr , raw pointer scenenode object. when try allocate new scenenode, following error: allocating object of abstract class type "scenenode".

here's code:

    class scenenode : public  sf::drawable,                   public  sf::transformable,                   private sf::noncopyable {      //overview: scenenode node scene graph. represents graphical element     //a typical scenenode (parent, children, transform)     //with transform containing several information:     //transform.pos = position of     //transform.rotation = rotation of      //the transformation of relative parent     //therefore, transform.pos position of this, relatively parent       //nb: - scenenode not copyable !     //    - it's abstract class  public:      //--------------------------------------------     //typedefs     //--------------------------------------------     typedef std::unique_ptr<scenenode> uniqueptr;     typedef sf::vector2f               position;  public:      //--------------------------------------------     //constructors     //--------------------------------------------     scenenode();         //requires: /         //modifies:         //effects: initializes this_post.parent = no parent         //         , this.children = { ⦰ }  public:      //--------------------------------------------     //public member functions     //--------------------------------------------     void attachchild(uniqueptr child);         //requires: child != nullptr         //modifies:         //effects: if child == nullptr, stops program;         //         else, this_post.children = this.children u { child }      uniqueptr detachchild(const scenenode& child);         //requires: /         //modifies:         //effects: if child in this.children, this_post.children = this.children \ child && returns unique_ptr child, don't catch let being freed      sf::transform getworldtransform() const;         //requires: /         //modifies: /         //effects: returns absolute transformation of      position getworldposition() const;         //requires: /         //modifies: /         //effects: returns absolute position of    private:      //--------------------------------------------     //representation     //--------------------------------------------     scenenode*             mparent;     std::vector<uniqueptr> mchildren;    };` 

what can ? in advance

it appears inheriting abstract interfaces sf::drawable not implementing pure virtual functions define (the draw() function in case of drawable). if implement functions in class should rid of compiler errors.