using System;

abstract public class AbstractPoint {

  public enum PointRepresentation {Polar, Rectangular}

  // We have not yet decided on the data representation of Point

  public abstract double X {
    get ; 
    set ;
  }

  public abstract double Y {
    get ; 
    set ;
  }

  public abstract double R {
    get ; 
    set ;
  }

  public abstract double A {
    get ; 
    set ;
  }

  public void Move(double dx, double dy){
    X += dx;  Y += dy;
  }

  public void Rotate(double angle){
    A += angle;
  }

  public override string ToString(){
    return  "(" + X + ", " + Y + ")" + " " +  "[r:" + R + ", a:" + A + "]  ";
  }

  protected static double RadiusGivenXy(double x, double y){
    return Math.Sqrt(x * x + y * y);
  }

  protected static double AngleGivenXy(double x, double y){
    return Math.Atan2(y,x);
  }

  protected static double XGivenRadiusAngle(double r, double a){
    return r * Math.Cos(a);
  }

  protected static double YGivenRadiusAngle(double r, double a){
    return r * Math.Sin(a);
  }

  
}