static void Main(string[] args) { var s = new Student("Alex"); s.SetKnowledge(new Knowledge(5)); University university = new University("CH.U.I."); University universityWithoutStudents = new University("Sad university"); university.AddStudent(new Student("Andrew Kostenko", new Knowledge(5))); university.AddStudent(new Student("Julia Veselkina", new Knowledge(4))); university.AddStudent(new Student("Maria Perechrest", new Knowledge(3))); university.AddStudent(new Student("Roma Danilyk", new Knowledge(4))); university.AddStudent(new Student("Oleg Pilipenko", new Knowledge(3))); university.AddStudent(s); Internship internship = new Internship("Interlink"); internship.SelectStudents(university); Console.WriteLine("List of internship's students:"); Console.WriteLine(internship.GetStudents()); Console.WriteLine(universityWithoutStudents.GetAverageKnowledge()); }