day13

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 file_change(src_file, src_info, dsc_info):
    '''文件修改功能 参数：修改文件路径  要修改的内容 修改后的内容'''
    with open(r'{}'.format(src_file), 'r', encoding='utf-8')as f:
        res = f.read()
        res.replace(f'{src_info}', f'{dsc_info}')
    with open(r'{}'.format(src_file), 'w', encoding='utf-8')as f1:
        f1.write(res)
        return '修改成功'

2、编写tail工具

def tail_access(file_name):
    '''  监控日志功能  '''
    with open(f'{file_name}', 'rb')as f:
        f.seek(0, 2)
        while True:
            res = f.readline()
            if not res:
                time.sleep(0.5)
            else:
                return res.decode('utf-8')

3、编写登录功能

def login():
    while True:
        user_name = input('请输入用户名：').strip()
        user_pwd = input('请输入密码：').strip()
        with open('user_info.txt', 'r', encoding='utf-8')as f:
            for line in f:
                username, password = line.strip().split(':')
                if user_name == username and user_pwd == password:
                    return True, '登录成功'
            else:
                return False, '用户名或密码错误'

4、编写注册功能

def register():
    user_name = input('请输入用户名：').strip()
    user_pwd = input('请输入密码：').strip()
    with open('user_info.txt', 'r', encoding='utf-8')as f:
        res = f'{user_name}:{user_pwd}'
        f.write(res)
        return '注册成功！'

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

import os

user_info = {
    'username': None
}

def select(user_name):
    '''用户登录校验功能'''
    with open('user_info.txt', 'r', encoding='utf-8')as f:
        for line in f:
            username, password, balance = line.strip().split(':')
            if user_name == username:
                return username, password, balance
        else:
            return False


def receive_money(user_name, money):
    '''用户接收转账功能'''
    with open('user_info.txt', 'r', encoding='utf-8')as f1, \
            open('user_info1.txt', 'w', encoding='utf-8')as f2:
        for line in f1:
            username, password, balance = line.strip().split(':')
            if user_name == username:
                balance = int(balance)
                balance += money
            res = f'{username}:{password}:{balance}\n'
            f2.write(res)
    os.remove('user_info.txt')
    os.rename('user_info1.txt', 'user_info.txt')

def login():
    '''登录功能'''
    while True:
        user_name = input('请输入用户名：').strip()
        user_pwd = input('请输入密码：').strip()
        flag = select(user_name)
        if flag:
            if user_pwd == flag[1]:
                user_info['username'] = user_name
                print('登录成功！')
                break
            else:
                print('用户名或密码错误！')
        else:
            print('用户不存在！')


def recharge():
    '''充值功能'''
    if user_info['username']:
        recharge_money = input('请输入充值金额：').strip()
        recharge_money = int(recharge_money)
        with open('user_info.txt', 'r', encoding='utf-8')as f1, \
                open('user_info1.txt', 'w', encoding='utf-8')as f2:
            for line in f1:
                username, password, balance = line.strip().split(':')
                if user_info['username'] == username:
                    balance = int(balance)
                    balance += recharge_money
                res = f'{username}:{password}:{balance}\n'
                f2.write(res)
        os.remove('user_info.txt')
        os.rename('user_info1.txt', 'user_info.txt')
    else:
        print('请先登录！')
        login()


def withdraw():
    '''提现功能'''
    if user_info['username']:
        with open('user_info.txt', 'r', encoding='utf-8')as f1, \
                open('user_info1.txt', 'w', encoding='utf-8')as f2:
            for line in f1:
                username, password, balance = line.strip().split(':')
                if user_info['username'] == username:
                    while True:
                        money = input('请输入提现金额：').strip()
                        money = int(money)
                        balance = int(balance)
                        if balance >= money:
                            balance -= money
                            break
                        else:
                            print('用户余额不足！')
                            continue
                res = f'{username}:{password}:{balance}\n'
                f2.write(res)
        os.remove('user_info.txt')
        os.rename('user_info1.txt', 'user_info.txt')
    else:
        print('请先登录！')
        login()


def transfer():
    '''转账功能'''
    if user_info['username']:
        while True:
            to_name = input('请输入转账用户：').strip()
            flag = select(to_name)
            if flag:
                with open('user_info.txt', 'r', encoding='utf-8')as f1, \
                        open('user_info1.txt', 'w', encoding='utf-8')as f2:
                    for line in f1:
                        username, password, balance = line.strip().split(':')
                        if user_info['username'] == username:
                            while True:
                                to_money = input('请输入转账金额：').strip()
                                to_money = int(to_money)
                                balance = int(balance)
                                if balance >= to_money:
                                    balance -= to_money
                                    print('转账成功')
                                    break
                                else:
                                    print('用户余额不足！')
                                    continue
                        res = f'{username}:{password}:{balance}\n'
                        f2.write(res)
                os.remove('user_info.txt')
                os.rename('user_info1.txt', 'user_info.txt')
                #调用转账用户接收功能
                receive_money(to_name, to_money)
                break
            else:
                print('转账用户不存在！')
    else:
        print('请先登录！')
        login()

def check_balance():
    '''查看余额功能'''
    if user_info['username']:
        with open('user_info.txt', 'r', encoding='utf-8')as f:
            for line in f:
                username,password , balance = line.strip().split(':')
                if user_info['username'] == username:
                    print(f'用户{username}余额为：{balance}')
    else:
        print('请先登录！')
        login()

def logout():
    '''退出功能'''
    if user_info['username']:
        user_info['username'] = None
    else:
        print('用户没有登录！')


#功能函数
func_dic = {
    '0': login,
    '1': recharge,
    '2': withdraw,
    '3': transfer,
    '4': check_balance,
    '5': logout
}


def run():
    while True:
        print('''
        '0',登录
        '1',充值
        '2',提现
        '3',转账
        '4',查询余额
        '5',退出登录
        ''')
        cmd = input('请输入功能编号：').strip()
        if not cmd.isdigit():
            print('请输入数字')
            continue
        elif cmd not in func_dic:
            print('请输入正确的编号')
            continue
        else:
            func_dic.get(cmd)()


if __name__ == '__main__':
    run()