auto save

my_app.py

 import tkinter
 import tkinter
 from tkinter import messagebox
 from tkinter import messagebox
+import json
 
 
 with open("user.txt","r",encoding="utf-8") as file:
 with open("user.txt","r",encoding="utf-8") as file:
-        info = f.read()
+        info = file.read()
         users = json.loads(info)
         users = json.loads(info)
 
 
 def login_to_reg():    # 登录界面转注册界面
 def login_to_reg():    # 登录界面转注册界面