static void Main(string[] args) { Bank bk = new Bank(); string output = "Press 0 to use the ATM, press 1 to manage your account,press n to exit"; while (true) { Show(output); string op = GetInput(); if (op=="n") { break; } switch (op) { case ("0"): { string op_atm; ATM atm = new ATM(bk); while (true) { Show("input any key to use ATM or Press n to exit"); op_atm = GetInput(); if (op_atm == "n") { break; } else { atm.Transaction(); } } } break;//ATM case ("1"): { string op_bank; while (true) { Show("input any key to manage your account or Press n to exit"); op_bank = GetInput(); if (op_bank == "n") { break; } else { bk.init(); } } } break;//Bank default: break; } } }