Today's Focus is object-oriented design. We will be working with the concept of bank accounts in order to explore more object-oriented code as well as a few other new topics.
- Create a class
- Create methods inside the class to perform actions
- Learn how Python does error handling
- Create a
Bank
class which will contain yourAccount
class and any future bank account logic. - Create an
Account
class which should have the following functionality:
- A new account should be created with an
ID
and an initialbalance
- Should have a
withdraw
method that accepts a single parameter which represents the amount of money that will be withdrawn. This method should return the updated account balance. - Should have a
deposit
method that accepts a single parameter which represents the amount of money that will be deposited. This method should return the updated account balance. - Should be able to access the current
balance
of an account at any time.
- A new account cannot be created with initial negative balance - this should
raise
anException
(leverage those Googling skills!) - The
withdraw
method does not allow the account to go negative - it should output a warning message and return the original un-modified balance
- Create an
Owner
class which will store information about those who own theAccounts
.- This should have info like name and address and any other identifying information that an account owner would have.
- Add an
owner
property to each Account to track information about who owns the account.- The
Account
can be created with anowner
, OR you can create a method that will add theowner
after theAccount
has already been created.
- The
- Create and use class methods
- Use a CSV file for loading data
- Update the
Account
class to be able to handle all of these fields from the CSV file used as input.- For example, manually choose the data from the first line of the CSV file and ensure you can create a new instance of your Account using that data
- Add the following class methods to your existing
Account
class.all_accounts
- returns a collection ofAccount
instances, representing all of the Accounts described in the CSV. See below for the CSV file specifications.find(id)
- returns an instance ofAccount
where the value of the id field in the CSV matches the passed parameter
Bank::Account
The data, in order in the CSV, consists of:
- ID - (Integer) a unique identifier for that Account
- Balance - (Integer) the account balance amount, in cents (i.e., 150 would be $1.50)
- OpenDate - (Datetime) when the account was opened
Bank::Owner
The data, in order in the CSV, consists of:
- ID - (Integer) a unique identifier for that Owner
- Last Name - (String) the owner's last name
- First Name - (String) the owner's first name
- Street Addess - (String) the owner's street address
- City - (String) the owner's city
- State - (String) the owner's state
To create the relationship between the accounts and the owners use the account_owners
CSV file.
The data for this file, in order in the CSV, consists of:
- Account ID - (Integer) a unique identifier corresponding to an account
- Owner ID - (Integer) a unique identifier corresponding to an owner
- Use inheritance to share some behavior across classes
- Enhance functionality built in Wave 1
Create a SavingsAccount
class which should inherit behavior from the Account
class. It should include the following updated functionality:
- The initial balance cannot be less than $10. If it is, this will
raise
anArgumentError
- Updated withdrawal functionality:
- Each withdrawal 'transaction' incurs a fee of $2 that is taken out of the balance.
- Does not allow the account to go below the $10 minimum balance - Will output a warning message and return the original un-modified balance
It should include the following new method:
-
add_interest(rate)
: Calculate the interest on the balance and add the interest to the balance. Return the interest that was calculated and added to the balance (not the updated balance).- Input rate is assumed to be a percentage (i.e. 0.25).
- The formula for calculating interest is
balance * rate/100
- Example: If the interest rate is 0.25% and the balance is $10,000, then the interest that is returned is $25 and the new balance becomes $10,025.
Create a CheckingAccount
class which should inherit behavior from the Account
class. It should include the following updated functionality:
- Updated withdrawal functionality:
- Each withdrawal 'transaction' incurs a fee of $1 that is taken out of the balance. Returns the updated account balance.
- Does not allow the account to go negative. Will output a warning message and return the original un-modified balance.
- Each withdrawal 'transaction' incurs a fee of $1 that is taken out of the balance. Returns the updated account balance.
withdraw_using_check(amount)
: The input amount gets taken out of the account as a result of a check withdrawal. Returns the updated account balance.- Allows the account to go into overdraft up to -$10 but not any lower
- The user is allowed three free check uses in one month, but any subsequent use adds a $2 transaction fee
reset_checks()
: Resets the number of checks used to zero
Create a MoneyMarketAccount
class which should inherit behavior from the Account
class.
- A maximum of 6 transactions (deposits or withdrawals) are allowed per month on this account type
- The initial balance cannot be less than $10,000 - this will
raise
anArgumentError
- Updated withdrawal logic:
- If a withdrawal causes the balance to go below $10,000, a fee of $100 is imposed and no more transactions are allowed until the balance is increased using a deposit transaction.
- Each transaction will be counted against the maximum number of transactions
- Updated deposit logic:
- Each transaction will be counted against the maximum number of transactions
- Exception to the above: A deposit performed to reach or exceed the minimum balance of $10,000 is not counted as part of the 6 transactions.
add_interest(rate)
: Calculate the interest on the balance and add the interest to the balance. Return the interest that was calculated and added to the balance (not the updated balance).- Note This is the same as the
SavingsAccount
interest.
- Note This is the same as the
reset_transactions
: Resets the number of transactions to zero