static void Main(string[] args) { Mediator mediator = new Mediator(); Teacher engin = new Teacher(mediator); engin.Name = "Engin"; mediator.Teacher = engin; Student derin = new Student(mediator); derin.Name = "Derin"; Student salih = new Student(mediator); salih.Name = "Salih"; mediator.Students = new List <Student> { derin, salih }; engin.SendWiewImagerUrl("slide.jpg"); engin.RecieveQuestion("is it true", salih); Console.ReadLine(); }