    class Circle : Point 
    {
        private double radius;
        public Circle()
        {
           //Defualt constructor
        }
        public Circle(int xValue, int yValue, double radiusValue)
            : base(xValue, yValue)
        {
            radius = radiusValue;
        }
        public double Radius
        {
            get
            {
                return radius;
            }
            set
            {
                if (radius >= 0)
                    radius = value;
            }
        }
        public override  double area()
        {
            return 3.14 * Radius * Radius;
        }
        public double diameter()
        {
            return Radius * 2;
        }
        public double Circumference()
        {
            return  3.14 * diameter ();
        }
        public override string ToString()
        {
            return "Center = " + base.ToString() +
                ", Radius = " + Radius;
        }
        public override string Name
        {
            get
            {
                return "Circle";
            }
        }
    }
