auto save

diy2.py

 username = "python"
 userpassword = "123456"
+i = 3
 while True:
-    name = input("请输入用户名:")
-    password = input("请输入密码:")
-    if name == username and password == userpassword:
-        print("登录成功!")
-    print("用户名和密码错误!请重新输入")
+    if i>0:
+        name = input("请输入用户名:")
+        password = input("请输入密码:")
+        if name == username and password == userpassword:
+            print("登录成功!")
+            break
+        elif name != username:
+            print("用户名不存在,请重新输入!")
+        else:
+            print("密码输入有误,请重新输入!")
+            i -= 1
+            print("你还有"+str(i)+"次输入机会！")
+    else:
+        print("亲，请带着身份证来警察局一趟！")
+        exit()
 print("欢迎来到贝尔编程!")
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