一、【登录密码的判断】
实现这个功能主要用到while循环和if-else判断，实现最多三次输入不正确就退出程序，实现锁定功能就要用到文件处理命令。
①、程序流程图
②、程序代码图
③、程序代码:
1 #Write the login interface: 2 #insert username and password. 3 #A welcome message is displayed after the authentication is successful. 4 #Lock the interface after three wrong entries. 5 username="root" 6 password='123' 7 count=0 8 while count<3: 9 user=input("Please input username:") 10 passw=input("\nPlease input password:") 11 if user==username and passw==password: 12 print("Welcome!\n") 13 break 14 else: 15 print("Access denied,please try again.\n") 16 count+=1 17 else: 18 print("You have tried three times,Interface locked.\n") ④、个人总结：
二、【三级菜单设计】
①、流程图
②、程序代码图
③、程序代码：
1 #Create a multilevel menu 2 #There are three levels in the menu. 3 #You can enter each submenu in turn. 4 5 shandong_list=['1.济南','2.泰安','3.青岛'] 6 jinan_list=['长清区','高新区','历下区'] 7 taian_list=['4.宁阳县','东平县'] 8 qingdao_list=['黄岛区','崂山区'] 9 ningyang_list=['东疏镇','乡饮乡','磁窑镇'] 10 b='back' 11 while b=='back': 12 print(shandong_list) 13 print("\nIf there are no number in front of the city,it means that's the last level of he meunu.") 14 a = input("Please chose one city number:") 15 if a=='1': 16 print(jinan_list) 17 elif a=='3': 18 print(qingdao_list) 19 elif a=='2': 20 while a=='2' or b=='2': 21 b='1' 22 print(taian_list) 23 print("\nIf there are no number in front of the city,it means that's the last level of he meunu.") 24 a =input("\nPlease chose one city number:") 25 if a=='4': 26 print(ningyang_list) 27 print("\nThis is the last level,if you want to back please input 2.") 28 b = input("\nplease input your choose:") 29 if b=='2': 30 continue 31 else: 32 break 33 else: 34 print(taian_list) 35 break 36 else: 37 break 38 print("\nPlease input 'back' return the upside menu or input any other key to quit.") 39 b=input("\nplease input your choose:") 40 if b=='back': 41 continue 42 else: 43 break ④、个人总结
上面两个程序都是运用简单的while和if实现了一些功能，如果能运用函数的调用或其他语法会让程序更完善。
来源：博客园
作者：Mr-Kitten
链接：https://www.cnblogs.com/Mr-Kitten/p/11780489.html