用户登陆系统

def login(username, password):
    ‘‘‘
    登录
    :param username:用户输入的用户名
    :param password: 用户输入的密码
    :return:验证成功
    ‘‘‘
    with open(‘userinfo.txt‘, ‘r‘, encoding=‘utf-8‘) as oplogin:
        for line in oplogin:
            if line.split(‘%%‘)[0] == username and line.split(‘%%‘)[1] == password:
                return True
    return False


def register(username, password):
    ‘‘‘
    注册
    :param username: 用户输入的用户名
    :param password: 用户输入的密码
    :return: 写入文件注册成功
    ‘‘‘
    with open(‘userinfo.txt‘, ‘a‘, encoding=‘utf-8‘) as opreg:
        opreg.write(‘\n‘ + username + ‘%%‘ + password)
        return print(‘注册成功‘)


def same(username):
    ‘‘‘
    查是否重复用户名
    :param username: 用户输入用户名
    :return:如果重复返回True，没有重复返回Flase
    ‘‘‘
    with open(‘userinfo.txt‘, ‘r‘, encoding=‘utf-8‘) as opsame:
        for line in opsame:
            line = line.strip()
            if line.split(‘%%‘)[0] == username:
                return True
    return False  # 这个return要在最外层，而不是在if语句里


def main():
    choice = input(‘1:login,2:register‘)
    if choice == ‘1‘:
        username = input(‘username‘)
        password = input(‘password‘)
        if login(username, password):
            print(‘登录成功‘)
        else:
            print(‘登录失败‘)
    if choice == ‘2‘:
        username = input(‘username‘)
        password = input(‘password‘)
        if same(username):
            print(‘用户名已被占用‘)
            main()
        else:
            register(username, password)


main()