作业day11

2020-06-15

# 1、编写文件修改功能，调用函数时，传入三个参数（修改的文件路径，要修改的内容，修改后的内容）既可完成文件的修改

def modify(file_path, old_contents, new_contents):
    with open(r'%s' % file_path, mode='r', encoding='utf-8') as f1, \
            open(r'new_file.txt', mode='w', encoding='utf-8') as f2:
        data = f1.read()
        res = data.replace(old_contents, new_contents)
        f2.write(res)
    import os
    os.remove(file_path)
    os.rename('new_file.txt', file_path)
    print("修改完成")

# 2、编写tail工具

def tail():
    import time
    with open("a.txt", mode='rb')as f:
        f.seek(0, 2)
        while True:
            line = f.readline()
            if len(line) == 0:
                time.sleep(0.1)
            else:
                print(line.decode('utf-8'), end="")

# 3、编写登录功能

def login():
    i = 0
    while i < 3:
        inp_name = input("请输入您的用户名：")
        inp_psw = input("请输入您的密码：")
        with open(r'registration.txt', mode='rt', encoding='utf-8') as f3:
            for line in f3:
                name, psw = line.strip('\n').split(':')
                if inp_name == name and inp_psw == psw:
                    print("登录成功！")
                    i = 3
                    break
            else:
                print("登录失败，请重新登录！")
                i += 1

# 4、编写注册功能

def register():
    tag = True
    while tag:
        l = []
        inp_name = input("请注册您的用户名：").strip()
        with open('registration.txt', mode='r', encoding='utf-8') as f1:
            for line in f1:
                info_name, *_ = line.strip('\n').split(':')
                l.append(info_name)
        if inp_name not in l:
            while tag:
                inp_psw = input("请注册您的密码（仅由数字组成）：").strip()
                if inp_psw.isdigit():
                    with open('registration.txt', mode='a', encoding='utf-8') as f2:
                        f2.write('%s:%s' % (inp_name, inp_psw))
                    print("注册成功！")
                    tag = False
                else:
                    print("密码格式错误")
        else:
            print("用户名已存在，请重新输入")

# 5、编写用户认证功能

def check():
    tag = True
    while tag:
        inp_name = input("请输入您的用户名：")
        inp_psw = input("请输入您的密码：")
        with open(r'registration.txt', mode='rt', encoding='utf-8') as f3:
            for line in f3:
                name, psw = line.strip('\n').split(':')
                if inp_name == name and inp_psw == psw:
                    print("认证成功！")
                    tag = False
                    break
            else:
                print("认证失败")

 

 

# 选做题：编写ATM程序实现下述功能，数据来源于文件db.txt
# 1、充值功能：用户输入充值钱数，db.txt中该账号钱数完成修改
# 2、转账功能：用户A向用户B转账1000元，db.txt中完成用户A账号减钱，用户B账号加钱
# 3、提现功能：用户输入提现金额，db.txt中该账号钱数减少
# 4、查询余额功能：输入账号查询余额

# 选做题中的选做题：登录功能
# 用户登录成功后，内存中记录下该状态，上述功能以当前登录状态为准，必须先登录才能操作