登陆和注册功能
代码如下

import json
user = []
with open('user.json', 'r') as fp:
    user = json.load(fp)


def region():
    while 1:
        user1 = input('请输入用户名：')
        password1 = input('请输入密码：')
        us = False
        true = False
        if user == []:
            print('此系统还没有人注册，请注册')
            print('是否注册：1.是 2.否')
            n = int(input('请选择：'))
            if n == 1:
                register()
            else:
                break
        for user2 in user:
            if user2['user'] == user1:
                us = True
                if user2['user'] == user1 and user2['password'] == password1:
                    true = True
        if us == False:
            print('用户名不存在！')
            break
        elif true:
            print('登陆成功！')
            break
        else:
            print('用户名或密码错误，请重新输入，是否重新输入：1.是 2.否')
            n = int(input('请选择：'))
            if n == 1:
                continue
            else:
                break


def register():
    while 1:
        user3 = input('请输入用户名：')
        password1 = input('请输入密码：')
        password2 = input('请确认密码：')
        name = False
        if password1 != password2:
            print('两次密码不一致，请重新输入！')
            continue
        for user2 in user:
            if user2['user'] == user3:
               name = True
        if name:
            print('用户名已存在,请重新输入!')
            continue
        user_ = {'user': user3, 'password': password1}
        user.append(user_)
        break
    with open('user.json', 'w') as fp:
        json.dump(user, fp)
    print('注册成功！')

while 1:
    print('==============================')
    print('|    欢迎来到学生管理系统    |')
    print('==============================')
    print('|        1.用户登陆          |')
    print('|        2.用户注册          |')
    print('==============================')
    n = int(input('请选择：'))
    if n == 1:
        region()
    elif n == 2:
        register()
    else:
        print('您已退出系统！')
        break