1、运行login.py
2、程序首先读取user.txt帐号信息和lock.txt被锁定帐号信息。
3、输入帐号，密码
4、判断：
　　如输入正确显示登录成功。
　　如输入帐号为锁定帐号，提示用户并退出。
　　如帐号名称或密码错误，可再重复输入2次，超过三次后退出程序。如果是系统账户将被锁定帐号写入lock.txt。

# 初始化账户字典，帐号锁定列表
userinfo = {}
lockinfo = []
# 读取账户信息及锁定帐号信息
with open("user.txt", "r") as f1, open("lock.txt", "r") as f2:
    while True:
        line = f1.readline().strip("\n")
        if not line:
            break
        else:
            userinfo[line.split(":")[0]] = line.split(":")[1]
    while True:
        line = f2.readline().strip("\n")
        if not line:
            break
        else:
            lockinfo.append(line)
# 对输入的帐号进行处理
lockflag = 0
while lockflag < 3:    # 控制输入小于3次
     lockflag += 1
     user = input("your name:")
     passwd = input("your password:")
     if user in lockinfo:
         print("this is lock account!")
         break
     if user in userinfo:
         if passwd == userinfo[user]:
             print("login ok!")
             break
         else:
             print("password error!")
             continue
     else:
         print("user is erro!")
         continue
else:
    with open("lock.txt", "a+") as f:
        f.write(user+‘\n‘)
    print("your account is be locked!")