static void Main(string[] args) { var customerManager = new CustomerManager(); customerManager.Add(new Customer() { Id = 4, FirstName = "Afet", LastName = "Agayeva" }); customerManager.Update(new Customer() { Id = 4, FirstName = "Afet", LastName = "Valiyeva" }); customerManager.Delete(new Customer() { Id = 4 }); //customerManager.Clear(); foreach (var customer in customerManager.GetAll()) { Console.WriteLine("{0} {1} {2}", customer.Id, customer.FirstName, customer.LastName); } var customers = customerManager.GetByName("VUQar"); Console.WriteLine("{0} {1} {2}", customers[0].Id, customers[0].FirstName, customers[0].LastName); }