static void Main(string[] args) { Console.Write("NHAP SO NGUOI: "); int n = Convert.ToInt32(Console.ReadLine()); List <Person> listPerson = new List <Person>(); List <Student> listStudent = new List <Student>(); List <Teacher> listTeacher = new List <Teacher>(); byte option = 9; while (option != 0) { Console.WriteLine(); Console.WriteLine("1. NHAP THONG TIN CHO SINH VIEN"); Console.WriteLine("2. NHAP THONG TIN CHO GIAO VIEN"); Console.WriteLine("3. XUAT THONG TIN CAC HOC SINH"); Console.WriteLine("4. XUAT THONG TIN CAC GIAO VIEN"); Console.WriteLine("5. TIM SINH VIEN CO DIEM CAO NHAT THUOC KHOA CNTT"); Console.WriteLine("6. TIM KIEM THONG TIN THEO TEN"); Console.WriteLine("0. LUU VA THOAT"); Console.Write("> "); option = Convert.ToByte(Console.ReadLine()); switch (option) { case 1: { if (listPerson.Count() == n) { Console.Write("\nSO LUONG NGUOI DA TOI DA! VUI LONG NHAP LUA CHON KHAC..\n"); break; } Student sv = new Student(); sv.Input(); listStudent.Add(sv); listPerson.Add(sv); break; } case 2: { if (listPerson.Count() == n) { Console.Write("\nSO LUONG NGUOI DA TOI DA! VUI LONG NHAP LUA CHON KHAC..\n"); break; } Teacher tc = new Teacher(); tc.Input(); listTeacher.Add(tc); listPerson.Add(tc); break; } case 3: { foreach (Student sv in listStudent) { sv.Output(); } break; } case 4: { foreach (Teacher tc in listTeacher) { tc.Output(); } break; } case 5: { List <Student> listSVKhoaCNTT = listStudent.Where(sv => sv.Khoa.ToLower() == "cntt").ToList(); float maxScore = listSVKhoaCNTT.Max(p => p.DiemTrungBinh); Console.WriteLine("\n== DANH SACH SINH VIEN CO DTB CAO NHAT VA THUOC KHOA CNTT =="); foreach (Student sv in listSVKhoaCNTT) { if (sv.DiemTrungBinh == maxScore) { sv.Output(); } } break; } case 6: { Console.Write("\nHAY NHAP TEN CAN TIM KIEM: "); string inputName = Console.ReadLine(); Person find = listPerson.FirstOrDefault(p => p.HoTen == inputName.ToLower()); Console.WriteLine("\n== DANH SACH TIM KIEM THEO TEN VUA NHAP =="); find.Output(); break; } default: break; } } Console.ReadLine(); }