using System;

public class Point {

  public enum PointRepresentation {Polar, Rectangular}
  private double r, a;    // polar data repr: radius, angle

  // Construct a point with polar coordinates
  public Point(double r, double a){
     this.r = r;
     this.a = a;
  }  

  // Construct a point, the representation of which depends
  // on the third parameter.
  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);
   }
  }  

  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);
  }

  // Remaining Point operations not shown
}