#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author:xuejp

import sys

#輸入使用者名稱密碼
username = input('username:')
password = input("password:")

#讀取檔案並轉化為字典
with open('./User','r') as f:
    result = dict(line.strip().split(':') for line in f if line)

#設定計數器
count = 0

#使用者是否存在
def if_user_exit():
    count = 0
 

    for key in result:
        if username == key:
            count+=1
    if count == 0:
        print('The user is not exist')
        sys.exit()
#檢查使用者是否被鎖
def if_user_lock():
    with open('./lock_user', 'r') as f:  # 檢車該使用者是否被lock
        for line in f.readlines():
            if username == line.strip():
                print('The user is locked'
 
)
                sys.exit()


if_user_exit()
if_user_lock()

while count < 3:
    if password == result.get(username): #使用者名稱密碼正確跳到登入介面
        info = '''welcome user {_username} login'''.format(_username=username)
        print(info)
        break
    else: #使用者名稱密碼不正確，告知登入失敗，計數器加一
        if_user_exit() #判斷第二次輸入的使用者是否存在
 

        count += 1
        if count == 3:  # 首先判斷是否錯誤三次
            print('sorry,the user %s is locked!' % (username))  # 第三次登入失敗告知使用者被鎖
            with open('./lock_user', 'a') as f_lock:  # 將使用者名稱寫到檔案中
                f_lock.write(username + '\n')
        else:
            print("login filed:three filed will be lock,only have {_count} changes".format(_count=3-count))
            username = input('username:')
            password = input("password:")

流程圖