auto save

diy2.py

 username = "python"
 username = "python"
 userpassword = "123456"
 userpassword = "123456"
+i=3
 while True:
 while True:
     name = input("请输入用户名:")
     name = input("请输入用户名:")
     password = input("请输入密码:")
     password = input("请输入密码:")
     if name == username and password == userpassword:
     if name == username and password == userpassword:
         print("登录成功!")
         print("登录成功!")
+        break
     print("用户名和密码错误!请重新输入")
     print("用户名和密码错误!请重新输入")
+    if name!=username:
+        print("用户名不存在!请重新输入")
+        continue
+    if password!=userpassword:
+        print("密码有误!请重新输入")
+        i=i-1
+        print("你还有",str(i),"次机会")
+        
 print("欢迎来到贝尔编程!")
 print("欢迎来到贝尔编程!")
\ No newline at end of file