8 作业：用户名密码 3次锁定

1:.基础需求

# 基础需求
_username = 'alex'
_password = '123'

count = 0
while count < 3:
    username = input('username:')
    password = input('password:')

    if username == _username and password == _password:
        print("----------Welcome %s-----"%username)
        break
    else:
        print('用户名或密码错误，请重新输入!')
    count += 1

else:
    print("-----you try more times------")

2.升级需求

# 升级需求
user_list = {
    'alex':{'password':'123'},
    'jack':{'password':'123'},
    }

with open('lock', 'r') as f1:
    lock_user = f1.read()

count = 0
while count < 3:
    username = input('请输入用户名：')
    if username == lock_user:
        print("用户名已经锁定")
    else:
        if username not in user_list:
            print("用户名不存在")
        else:
            password = input('请输入密码：')
            if password == user_list[username]['password']:
                print("欢迎%s"%username)
                break
            else:
                print("密码错误，请重新输入")
    count += 1
    if count == 3:
        with open('lock', 'w') as f2:
            f2.write(username)

else:
    print("----输入超过3次，用户被锁定---")

# bug:锁定的是第三次输入的用户名，
#      锁定文件，直接覆盖，
#      应该追加用户，如何实现？