Problem description:

Write a python application to simulate a Password Storage and Management system. The purpose of

this assignment is to gain experience in python$$s loop $($while and for$)$ structure, condition structure,

sequence, and basic I$/$O$.$

Design solution:

The program initially provides a menu to the user. The user can choose an operation by entering the

number associated with that option as input. The three operations of the menu are explained below.

$1.$ Add username and password to the database: The program asks the user to input a username and

password. There are no specifications for the username. However, the password must consist of two

upper case letters and four lower case letters in any order. Each of the letters in the password must

be separated by the symbol $.$ The password should not contain any other characters $($digits$,$ special

symbols, etc.$)$ at all. An example username can be $$JaneDoe$$ and a password can be $$a$-$C$-$K$-$t$-$x$-$a$.$ The

program will go on to check whether the password meets these requirements or not. If successful,

the program joins the username and password by a $$:$.$ An example would look like $$JaneDoe:a$-$C$-$K t$-$x$-$a$.$ This string will then be appended to the global $$database$$ list.

Three lists, $$upper$\_$case$\_$letters$$ list of all letters in upper case

$$lower$\_$case$\_$letters$$ list of all letters in lower case

$$database$$ list of $$username:password$$ strings

will be provided to you in the template. You can use these lists accordingly. If not successful, print the

error message providing the reason along with the number of upper$-$ and lower$-$case letters in the

password entered by the user.

Please note: We assume that all the usernames in the $$database$$ list are unique. So$,$ when providing

the username as input please check that you are not giving any username from the database list.

$2.$ Displaying the list of passwords and usernames: On selecting this option, the program outputs all

the usernames and passwords present in the database at that time. You will have to split the

username and password from the $$username:password$$ string explicitly and print them separately.

Please do not print the whole sequence type as$-$is$.$

$3.$ Update the password of an existing user: The program asks the user to input the username for which

the password is to be updated from the $$database$$ list. It then finds the particular

$$username:password$$ string associated with the input username and updates the

$$username:password$$ string from the $$database$$ list. Display an informational message once updated. $4.$ Exit$/$terminate the program.

If the user enters any other option, display a message stating that the option is invalid and a request to

try again.