save project

3.py

+username='python'
+userpassword='123456'
+while True:
+    name = input("请输入用户名:")
+    password = input("请输入密码:")
+    if name == username and password == userpassword:
+        print("成功登陆")
+        break
+    elif name != username :
+        print("用户名错误，请重新输入")
+    else:
+        print("密码错误，请重新输入")
+    

diy1.py

+username='python'
+userpassword='123456'
+while True:
+    name = input("请输入用户名:")
+    password = input("请输入密码:")
+    if name == username and password == userpassword:
+        print("成功登陆")
+    elif name == username and password != userpassword:
+        print("密码错误，请重新输入")
+    elif name != username and password == userpassword:
+        print("用户不存在，请重新输入")
+    elif name != username and password != userpassword:
+        print("用户不存在，请重新输入")