import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class DoubleVector{
  double x;//java.io.Serializable
  double y;
  double v;
  double size;
  public DoubleVector()
    {
      x=0.0;y=0.0;size=0.0;v=0.0;
    }
  public DoubleVector(double dx,double dy)
    {
      x = dx;
      y = dy;
      size = getSize(x,y);
      v=0.0;
    }
  private double getSize(double dx,double dy)
    {
      return Math.sqrt((double)((dx*dx)+(dy*dy)));
    }
}