auto save

diy.py

+i=3
+username="python"
+userpassword="142857"
+while True:
+    if i!=0:
+        yourname=input("请输入您的用户账号：")
+        yourpassword=input("请输入您的用户密码：")
+        i-=1
+        if yourname==username and yourpassword==userpassword:
+            print("登录成功")
+            break
+        if yourname!=username:
+            print("用户名不存在，请重新输入！")
+            continue
+        if yourpassword!=userpassword:
+            print("用户密码不存在，请重新输入！")
+    else:
+        print("您的帐户已被冻结！")
+        exit()
+print("欢迎来到贝尔编程！")
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