// A versatile version of class Point with Rotation and internal methods
// for rectangular and polar coordinates. 

using System;

public class Point {

  public enum PointRepresentation {Polar, Rectangular}

  private double r, a;            
                                  
  public Point(double x, double y){
     r = RadiusGivenXy(x,y);
     a = AngleGivenXy(x,y);
  }

  public Point(double par1, double par2, PointRepresentation pr){  
   if (pr == PointRepresentation.Polar){                           
     r = par1; a = par2;
   } 
   else {
     r = RadiusGivenXy(par1,par2);
     a = AngleGivenXy(par1,par2);
   }
  }

  public double X {                             
    get {return XGivenRadiusAngle(r,a);}        
  }

  public double Y {                             
    get {return YGivenRadiusAngle(r,a);}        
  }


  public double Radius {                        
    get {return r;}                             
  }

  public double Angle{                          
    get {return a;}                             
  }   

  public void Move(double dx, double dy){
    double x, y;
    x = XGivenRadiusAngle(r,a);   y = YGivenRadiusAngle(r,a); 
    r = RadiusGivenXy(x+dx, y+dy);
    a = AngleGivenXy(x+dx, y+dy);
  }

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

  public override string ToString(){
    return  "(" + XGivenRadiusAngle(r,a) + "," + YGivenRadiusAngle(r,a) + ")";   
  }


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

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

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

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

  
}