static void Main(string[] args) { var s = new Student("Alex"); s.SetKnowledge(new Knowledge(4)); University university = new University("CH.U.I."); university.AddStudent(s); university.AddStudent(new Student("Andrew Kostenko", new Knowledge(2))); university.AddStudent(new Student("Julia Veselkina", new Knowledge(2))); university.AddStudent(new Student("Maria Perechrest", new Knowledge(5))); Internship internship = new Internship("Interlink"); internship.SelectStudentsFromUniversity(university); Console.WriteLine("List of internship's students:"); Console.WriteLine(internship.GetStudents()); }