Question
3. Look at the following description of a problem domain:
The bank offers the following types of accounts to its customers: savings accounts,checking accounts, and money market accounts. Customers are allowed to deposit money into an account (thereby increasing its balance), withdraw money from an account
(thereby decreasing its balance), and earn interest on the account. Each account has an interest rate.
Assume that you are writing a program that will calculate the amount of interest earned for a bank account.
a. Identify the potential classes in this problem domain.
b. Refine the list to include only the necessary class or classes for this problem.
c. Identify the responsibilities of the class or classes.
Answer
a. Potential classes in this problem domain could include:
- Bank (representing the bank itself)
- Customer (representing a bank customer)
- Account (representing a bank account)
- SavingsAccount (a specific type of account)
- CheckingAccount (a specific type of account)
- MoneyMarketAccount (a specific type of account)
b. Refined list of necessary classes for this problem:
- Customer
- Account (parent class for all types of accounts)
- SavingsAccount (inherits from Account)
- CheckingAccount (inherits from Account)
- MoneyMarketAccount (inherits from Account)
c. Responsibilities of the classes:
- Customer:
- Maintain customer information (name, address, etc.)
- Interact with accounts (deposit, withdraw, earn interest)
- Account:
- Hold common attributes and methods shared by all types of accounts:
- Account number
- Balance
- Interest rate
- Deposit money
- Withdraw money
- Calculate interest earned
- Hold common attributes and methods shared by all types of accounts:
- SavingsAccount (subclass of Account):
- Specific behavior related to savings accounts
- CheckingAccount (subclass of Account):
- Specific behavior related to checking accounts
- MoneyMarketAccount (subclass of Account):
- Specific behavior related to money market accounts
Each class will have its own set of attributes and methods specific to its responsibilities within the problem domain. The Account class will serve as the parent class for all types of accounts, providing a common interface and shared functionality, while the subclassed accounts will have additional behaviors unique to their specific types.