#  实现用户输入用户名和密码，当用户名为seven且密码为123时，显示登录成功，否则失败，失败时允许重复输入三次。 count = 0 while count < 3: username = input("Please enter your username: ") password = input("Please enter your password: ") if username == "seven" and password == "123": print("login successful.") break else: print("login failed.") count += 1 if count == 3: print("the max input is 3 times. ")