using System;

public class Point3D: Point2D {

  private double z;

  public Point3D(double x, double y, double z):
         base(x,y){
   this.z = z;
  }

  public double Z{
    get {return z;}
  }

  public void Move(double dx, double dy, double dz){
    base.Move(dx, dy);
    z += dz;
  }

  public override string ToString(){
    return "Point3D: " + "(" + X + ", " + Y + ", " + Z + ")" + ".";
  }
}