#!/usr/bin/env python

 import sys

 import getpass

 afile = 'afile'

 bfile = 'bfile'

 circulation_num=0  #循环次数初始基数

 def deny_account(username):

         print("This account already locked!")

         with open(bfile, 'a+') as bf:     #此处最好为a+模式，本人之前使用a模式错误账号无法写入

             bf.write(username + '\n')

 #循环开始

 while circulation_num<3:

         username = input("\033[32;1mPlease input your username:\033[0m")

         flag = False

         with open(afile, 'r') as af:

                 for line in af.readlines():

                         user,pwd=line.strip().split()

                         if username==user:

                                 password=getpass._raw_input('Please input password:').strip()

                                 if username==user and password ==pwd:

                                     print('success!')

                                     flag = True

                                     break

                                 else:

                                      print('password error,please try again!')

                         else:

                             if circulation_num < 3:

                               print('User doesn`t exist!')

                               circulation_num += 1

                         break

         if flag == True:

                 print('Welcome %s come in TG!' % username)

                 break

 else:

     deny_account(username)