_user ="alex" _passwd = "abc123" counter = 0 while counter <3: username = input("Username:") password = input("Password:") if username == _user and password == _passwd : print("Welcome %s login...." % _user) break #跳出,中断 else: print("Invalid username or password !") counter += 1 if counter == 3: keep_going_choice = input("还想玩么?[y/n]") if keep_going_choice == "y": counter = 0 else : print ( " Shouldn't be ashamed, you rascal, Xiaohu. " )