Object oriented project hands on

ATM machine simulator

The main goal of this hands on session is to build an atm machine simulator. You should download the atm_simulator.py module into your home dir.

The project counts with a single file, a python3 module that holds the classes for the ATMMachine itself and the Account class.

Assignments

1. Fill the missing methods: In this assignment you should fill the missing methods and check if the ATM machine is functioning correctly.

2. Design a solution for generating the Account number. Check-out the random() operation. Is that a good way to generate accounts numbers? Can you guarantee that no number appears twice?

   • Think of alternative ways to store the latest account number and derive the next one from it.

3. For each operation you have to go through (possibly) the whole list of accounts in order to retrieve the account which number has been passed as a parameter. Do you really need to do this? Think about the data structures presented in previous classes. Is there a better way to perform this search?

4. Create the following sub-classes: In this assignment you have to create two specializations for the Account class (the corresponding operations should be rewritten):

   • CheckingAccount: This class has the following restrictions:
     • Only 4 free transfers. There is a fee value of 5.0 for each transfer after the 4th.
     • Only 5 free balance checking operation. There is a fee value of 1.00 after the 5th balance checking operation.
   • SavingsAccount: This class has the following restrictions:
     • Only 3 free withdrawals. There is a fee value of 2.00 for each withdrawal after the 3rd.
     • No free transfer. Each transfer has a fee value of 1.00.

5. Check if the account balance allows the requested operation (insufficient funds). If it is not the case, the user should be warned of his/her current situation.

6. Enhance your balance checking structure by adding Exceptions, in case the client has not enough funds to perform the requested operation. Exceptions in Python are sub-classes of the basic exception class Exception:

   class NotEnoughFundsException(Exception):
       def __init__(self, message):
           self.value = message        

   In order to signal the exceptional behaviour use the raise command:

   if balance <= amount:
       raise NotEnoughFundsException("Check your Balance before")

   In order to deal with the exceptional behaviour use the try: .. except .. construction:

   try:
       account.withdraw(amount)
   except NotEnoughFundsException:
       print("Dear client, you should check your balance 
           before performing this operation")

   Question: Which class do you think should be responsible for raising the exception and which should be responsible for dealing with it?

7. Implement a new exception in case an operation resulted in a fee. Present a message for the client if that is the case.

8. Implement the bank statement functionality. Each operation should be logged at an special list of Transaction objects (create the Transaction class). For each transaction you shoud log the type of transaction, the date and also the amount involved. Update the menu and the ATMMachine class to support this new operation.