public static void FillAddressBook(AddressBook addressBook) { int choice; do { Console.WriteLine("\nMenu : \n1.Add Contact \n2.Edit Contact \n3.Delete Contact\n0.Exit"); choice = Convert.ToInt32(Console.ReadLine()); switch (choice) { case 1: Contact contact = new Contact(); SetContactDetails(contact); addressBook.AddContact(contact); break; case 2: Console.WriteLine("Enter the Phone Number of Contact you wish to Edit"); long phoneNumber = long.Parse(Console.ReadLine()); int index = addressBook.FindByPhoneNum(phoneNumber); if (index == -1) { Console.WriteLine("No Contact Exists With Following Phone Number"); continue; } else { Contact contact2 = new Contact(); SetContactDetails(contact2); addressBook.ContactList[index] = contact2; Console.WriteLine("Contact Updated Successfully"); } break; case 3: Console.WriteLine("Enter the First Name of Contact you wish to delete"); string fname = Console.ReadLine(); int idx = addressBook.FindByFirstName(fname); if (idx == -1) { Console.WriteLine("No Contact Exists with Following First Name"); continue; } else { addressBook.DeleteContact(idx); Console.WriteLine("Contact Deleted Successfully"); } break; } } while (choice != 0); }