public class Line {
   Point start;
   Point end;

   public Line(Point start, Point end) {
       this.start = start;
       this.end = end;
   }
   public String toString() {
       return "start: " + start + " end: " + end;
   }
   public double length(double l) {
       l = start.distance(end);
       return l;
   }
   public static void main(String[] args) {
       Point p1 = new Point(1, 1);
       Point p2 = new Point(4, 4);
       Line l1 = new Line(p1, p2);
       System.out.println(l1);
       System.out.println(l1.length(l));
   }
}