member functions in pure abstract classes

    #include <vector>
    #include <memory>
    #include <iostream>

    class Shape;

    typedef std::unique_ptr<Shape> shape_ptr;

    class Shape{

        public:

            Shape(){};
            virtual ~Shape(){std::cout << "Shape destructor: " << this << std::endl;};

            virtual void draw() const = 0;
            virtual float area() const = 0;

            virtual shape_ptr clone() const = 0;
            virtual shape_ptr create() const = 0;

            static shape_ptr defineRectangle(int, int );
            static shape_ptr defineCircle(float);
    };

    class Rectangle:public Shape{
        public:

            typedef std::unique_ptr<Rectangle> rectangle_SmartPtr;

            Rectangle(int height=0, int width=0):m_Height(height),m_Width(width){};
            Rectangle(const Rectangle & rect):m_Height(rect.m_Height),m_Width(rect.m_Width){};
            ~Rectangle(){};

            virtual void draw() const;
            virtual float area() const;


            virtual shape_ptr clone() const{ return shape_ptr(new Rectangle(*this)); };
            virtual shape_ptr create() const{ return shape_ptr(new Rectangle()); };

        private:
            int m_Height;
            int m_Width;
    };


    class Circle:public Shape{
        public:

            typedef std::unique_ptr<Circle> circle_SmartPtr;

            Circle(float radius=0):m_Radius(radius){};
            Circle(const Circle & other):m_Radius(other.m_Radius){};
            ~Circle(){std::cout << "Circle destructor: " << this << std::endl; };

            virtual void draw() const;
            virtual float area() const;

            virtual shape_ptr clone() const{ return shape_ptr(new Circle(*this)); };
            virtual shape_ptr create() const{ return shape_ptr(new Circle()); };

        private:

            float m_Radius;
    };

    /////////////////////////////////////////////////////////////////////
    shape_ptr Shape::defineRectangle(int height, int width){
        shape_ptr ptrRectangle = shape_ptr(new Rectangle(height, width));
        return (ptrRectangle);
    }

    shape_ptr Shape::defineCircle(float radius){
        shape_ptr ptrCircle = shape_ptr(new Circle(radius));
        return (ptrCircle);
    }

    /////////////////////////////////////////////////////////////////////

    void Rectangle::draw() const{
        std::cout << "draw rectangle at address: " << this << std::endl;
    }

    float Rectangle::area() const{
        float area = static_cast<float>(m_Height*m_Width);
        std::cout << "this is the Rectangle's area: " << area << std::endl;
        return area;
    }

    /////////////////////////////////////////////////////////////////

    void Circle::draw() const{
        std::cout << "draw circle at address: " << this << std::endl;
    }

    float Circle::area() const{
        float area = static_cast<float>(m_Radius*2*3.1415);
        std::cout << "this is the Circle's area: " << area << std::endl;
        return area;
    }

    int main( int argc, char ** argv ){


        std::vector<std::unique_ptr<Shape> > vect;
        vect.push_back(Shape::defineCircle(10));
        vect.push_back(Shape::defineRectangle(5, 4));
        vect.push_back(std::unique_ptr<Shape>(new Circle(10)));
        vect.push_back(std::unique_ptr<Shape>(new Rectangle(5,4)));

        exit(EXIT_SUCCESS);
    }