C#

public  interface ITestPoint
    {
         double PointDistance();
         void OutPoint();
         void SetPoint(double x,double y,double _x,double _y);
    }
    class Point :ITestPoint
    {
        public double x1, x2, y1, y2;

        public double PointDistance()
        {
            return Math.Sqrt(Math.Pow(x2 - x1, 2) + Math.Pow(y2 - y1, 2));
        }
        public void OutPoint()
        {
            Console.WriteLine("Point One({0},{1}); Point Two({2},{3})",x1,y1,x2,y2);
        }
       public void SetPoint(double x,double y,double _x,double _y)
        {
            x1 = x;
            y1 = y;
            x2 = _x;
            y2 = _y;
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Point p = new Point();

            p.SetPoint(2,3,5,8);
            p.OutPoint();
            Console.WriteLine(p.PointDistance());
            Console.ReadLine();
        }
    }