static void Main(string[] args) { customer customer1 = new customer(); customer1.ID = 101; customer1.name = "Mark"; customer customer2 = new customer(); customer2.ID = 102; customer2.name = "John"; customer customer3 = new customer(); customer3.ID = 103; customer3.name = "Sally"; customer customer4 = new customer(); customer4.ID = 104; customer4.name = "Mary"; customer customer5 = new customer(); customer5.ID = 105; customer5.name = "Daniel"; Queue <customer> queueOfCustomers = new Queue <customer>(); queueOfCustomers.Enqueue(customer1); queueOfCustomers.Enqueue(customer2); queueOfCustomers.Enqueue(customer3); queueOfCustomers.Enqueue(customer4); queueOfCustomers.Enqueue(customer5); foreach (customer c in queueOfCustomers) { Console.WriteLine("{0} - {1}", c.ID, c.name); } Console.WriteLine(""); customer b = queueOfCustomers.Peek(); // return the desired stuff without removing any member Console.WriteLine("{0} - {1}", b.ID, b.name); Console.WriteLine(""); customer c1 = queueOfCustomers.Dequeue(); //remove the first member and return the desired stuff foreach (customer a in queueOfCustomers) { Console.WriteLine("{0} - {1}", a.ID, a.name); } Console.WriteLine(""); Console.WriteLine("Total number {0}", queueOfCustomers.Count); if (queueOfCustomers.Contains(customer1)) { Console.WriteLine("customer exist"); } else { Console.WriteLine("Customer doesnot exist"); } Console.ReadKey(); }