static void Main(string[] args) { FileStream fs = new FileStream("candidates.xml", FileMode.OpenOrCreate); var s1 = new Student("Ivan", new Knowledge(80)); var s2 = new Student("Dany", new Knowledge(0)); var s3 = new Student("Mark", new Knowledge(100)); Student[] stud = new Student[] { s1, s2, s3 }; XmlSerializer formatter = new XmlSerializer(typeof(Student[])); using (fs) { formatter.Serialize(fs, stud); } var s = new Student("Alex"); University university = new University("CH.U.I."); university.AddStudent(new Student("Andrew Kostenko", new Knowledge(80))); university.AddStudent(new Student("Julia Veselkina", new Knowledge(70))); university.AddStudent(new Student("Maria Perechrest", new Knowledge(60))); s.SetKnowledge(new Knowledge(80)); Internship internship = new Internship("Interlink"); foreach (var student in university.students) { internship.candidates.Add(student); } internship.candidates.Add(s); internship.GetCandidatesFrom(fs = new FileStream("candidates.xml", FileMode.OpenOrCreate)); internship.GetStudents(university, internship.candidates); Console.WriteLine("List of internship's students:"); Console.WriteLine(internship.ShowBestStudents()); Console.ReadLine(); }