import java.awt.*;
import java.applet.*;
import java.lang.*;
import java.util.*;

public class UniVettore{

      private protected double x,y,xi,yi;

      public UniVettore(int px,int py,int pxi,int pyi){
         
          this.x = px;
          this.y = py;
          this.xi = (pxi-px)/Math.sqrt((double) (px-pxi)*(px-pxi)+(py-pyi)*(py-pyi));
          this.yi = (pyi-py)/Math.sqrt((double) (px-pxi)*(px-pxi)+(py-pyi)*(py-pyi));
         
      }

      public double getDx(){

          return x-xi;

      }

      public double getDy(){

          return y-yi;

      }

}