using System;

​

namespace Points

{               

    public class Point2D

    {

        protected int _x;

        protected int _y;

        public int X

        {

            get { return _x; }

            set { _x = value; }

        }

        public int Y

        {

            get { return _y; }

            set { _y = value; }

        }

        public Point2D(int x, int y)

        {

            X = x; Y = y;

        }

        public Tuple<int, int> GetCoordinates()

        {

            return Tuple.Create(_x, _y);

        }

        public override string ToString()

        {

            return String.Format("Point({0}, {1})", _x, _y);

        }

    }

    public class Point3D : Point2D

    {

        private int _z;

        public int Z

        {

            get { return _z; }

            set { _z = value; }

        }

        public Point3D(int x, int y, int z) : base(x, y)

        {

            Z = z;

        }

        public new Tuple<int, int, int> GetCoordinates()

        {

            return Tuple.Create(_x, _y, _z);

        }

        public override string ToString()

        {

            return String.Format("Point({0}, {1}, {2})", _x, _y, _z);

        }

    }

}

​

namespace PointTesting

{

    using Points;

    public class Program

    {

        public static void Main(string[] args)

        {

            Point2D p2 = new Point2D(

        }

    }

}