auto save

diy2.py

 username = "python"
 userpassword = "123456"
+i=3
 while True:
+    if i>0:
         name = input("请输入用户名:")
         password = input("请输入密码:")
         if name == username and password == userpassword:
@@ -8,6 +10,10 @@ while True:
             break
         if name != username:
             print("账号错误")
+            continue
         if password != userpassword:
             print("密码错误")
+        i=i-1
+    else:
+        exit()
 print("欢迎来到贝尔编程!")
\ No newline at end of file