Worksheet 9 - OOP Class BankAccount example

Bank Account Class

Here’s another simple object-oriented programming (OOP) example to help students practice. This one involves creating a Bank Account class, which simulates the basic functionality of a bank account. Like the previous example, it's designed for easy expansion.

# Simple Bank Account Class Example

class BankAccount:
    def __init__(self, account_holder, balance=0):
        """Initialize the account holder's name and balance."""
        self.account_holder = account_holder   # Account holder's name
        self.balance = balance                 # Initialize with an optional balance (default is 0)

    def deposit(self, amount):
        """Deposit money into the account."""
        if amount > 0:
            self.balance += amount
            print(f"Deposited ${amount}. New balance: ${self.balance}.")
        else:
            print("Deposit amount must be positive!")

    def withdraw(self, amount):
        """Withdraw money from the account."""
        if amount > 0 and amount <= self.balance:
            self.balance -= amount
            print(f"Withdrew ${amount}. Remaining balance: ${self.balance}.")
        elif amount > self.balance:
            print("Insufficient funds!")
        else:
            print("Withdrawal amount must be positive!")

    def display_balance(self):
        """Display the current balance."""
        print(f"Account balance: ${self.balance}")

if __name__ == '__main__':
    # Create an instance of the BankAccount class
    my_account = BankAccount('John Doe', 100)  # Initial deposit of $100

    # Display the current balance
    my_account.display_balance()

    # Perform a deposit
    my_account.deposit(50)  # Deposit $50

    # Perform a withdrawal
    my_account.withdraw(30)  # Withdraw $30

    # Attempt to withdraw more than the balance
    my_account.withdraw(150)  # Insufficient funds example

    # Display the final balance
    my_account.display_balance()

Explanation of the Code

Class Definition: BankAccount

• The class is defined to simulate a simple bank account.
• The __init__ method initializes the account holder’s name and an optional balance (default is 0).

Methods:

• deposit(self, amount): Adds money to the account, ensuring the amount is positive.
• withdraw(self, amount): Withdraws money from the account, ensuring the amount does not exceed the balance.
• display_balance(self): Prints the current account balance.

Main Script:

• An instance of the BankAccount class is created with an initial deposit.
• The program demonstrates depositing and withdrawing money and checks for insufficient funds.
• It prints the balance after each transaction.

Expanding the Program

Students can expand this example in several ways:

• Add Interest: Implement a method to apply interest to the account balance.
• Overdraft Protection: Add an overdraft limit and handle what happens when a withdrawal exceeds the overdraft limit.
• Multiple Accounts: Create a system to manage multiple bank accounts (e.g., savings and checking).
• Transaction History: Add a feature that tracks and prints all deposits and withdrawals.

This example builds upon the basics of OOP and encourages students to experiment with new features and functionalities.