Banking Program in Python

class BankAccount:
    def __init__(self, owner, balance=0):
        self.owner = owner
        self.balance = balance

    def deposit(self, amount):
        if amount > 0:
            self.balance += amount
            print(f"${amount} deposited. New balance: ${self.balance}")
        else:
            print("Deposit amount must be positive.")

    def withdraw(self, amount):
        if 0 < amount <= self.balance:
            self.balance -= amount
            print(f"${amount} withdrawn. New balance: ${self.balance}")
        else:
            print("Invalid withdrawal amount or insufficient funds.")

    def get_balance(self):
        return self.balance

    def transfer(self, amount, other_account):
        if 0 < amount <= self.balance:
            self.balance -= amount
            other_account.balance += amount
            print(f"${amount} transferred to {other_account.owner}. New balance: ${self.balance}")
        else:
            print("Invalid transfer amount or insufficient funds.")

    def __str__(self):
        return f"Account owner: {self.owner}\nAccount balance: ${self.balance}"


def main():
    print("Welcome to the Banking System")
    
    accounts = {}
    
    while True:
        print("\nOptions:")
        print("1. Create Account")
        print("2. Deposit")
        print("3. Withdraw")
        print("4. Check Balance")
        print("5. Transfer")
        print("6. Exit")
        choice = input("Choose an option: ")

        if choice == "1":
            owner = input("Enter the account owner's name: ")
            if owner in accounts:
                print("Account already exists.")
            else:
                accounts[owner] = BankAccount(owner)
                print(f"Account created for {owner}.")
                
        elif choice == "2":
            owner = input("Enter the account owner's name: ")
            if owner in accounts:
                amount = float(input("Enter the amount to deposit: "))
                accounts[owner].deposit(amount)
            else:
                print("Account not found.")

        elif choice == "3":
            owner = input("Enter the account owner's name: ")
            if owner in accounts:
                amount = float(input("Enter the amount to withdraw: "))
                accounts[owner].withdraw(amount)
            else:
                print("Account not found.")

        elif choice == "4":
            owner = input("Enter the account owner's name: ")
            if owner in accounts:
                print(f"Current balance: ${accounts[owner].get_balance()}")
            else:
                print("Account not found.")

        elif choice == "5":
            from_owner = input("Enter the sender's account owner's name: ")
            to_owner = input("Enter the receiver's account owner's name: ")
            if from_owner in accounts and to_owner in accounts:
                amount = float(input("Enter the amount to transfer: "))
                accounts[from_owner].transfer(amount, accounts[to_owner])
            else:
                print("One or both accounts not found.")

        elif choice == "6":
            print("Thank you for using the Banking System. Goodbye!")
            break

        else:
            print("Invalid option. Please choose again.")

if __name__ == "__main__":
    main()

Explanation

BankAccount Class

The BankAccount class encapsulates the details and operations for a single bank account.

Methods:

• __init__(self, owner, balance=0): This is the constructor method that initializes the account with the owner's name and an optional starting balance (default is 0).
  • self.owner stores the account owner's name.
  • self.balance stores the account balance.
• deposit(self, amount): Adds the specified amount to the account balance if the amount is positive.
  • Prints a confirmation message showing the deposited amount and the new balance.
  • Prints an error message if the deposit amount is not positive.
• withdraw(self, amount): Subtracts the specified amount from the account balance if the amount is positive and less than or equal to the current balance.
  • Prints a confirmation message showing the withdrawn amount and the new balance.
  • Prints an error message if the withdrawal amount is invalid or if there are insufficient funds.
• get_balance(self): Returns the current balance of the account.
• transfer(self, amount, other_account): Transfers the specified amount from the current account to another account if the amount is positive and less than or equal to the current balance.
  • Prints a confirmation message showing the transferred amount, the recipient's account owner, and the new balance.
  • Prints an error message if the transfer amount is invalid or if there are insufficient funds.
• __str__(self): Returns a string representation of the account, including the owner's name and the balance.

Main Function

The main function manages user interaction and the overall flow of the banking system.

Key Components:

• Welcome Message: Prints a welcome message when the program starts.
• Accounts Dictionary: A dictionary named accounts is used to store multiple BankAccount objects. The keys are the account owners' names, and the values are the corresponding BankAccount objects.
• Main Menu Loop: The program enters an infinite loop that displays a menu of options and processes user input.

Menu Options:

• Option 1: Create Account
  • Prompts the user to enter the account owner's name.
  • Checks if the account already exists. If not, it creates a new BankAccount object and adds it to the accounts dictionary.
• Option 2: Deposit
  • Prompts the user to enter the account owner's name and the deposit amount.
  • If the account exists, it calls the deposit method on the corresponding BankAccount object.
• Option 3: Withdraw
  • Prompts the user to enter the account owner's name and the withdrawal amount.
  • If the account exists, it calls the withdraw method on the corresponding BankAccount object.
• Option 4: Check Balance
  • Prompts the user to enter the account owner's name.
  • If the account exists, it calls the get_balance method on the corresponding BankAccount object and prints the balance.
• Option 5: Transfer
  • Prompts the user to enter the sender's account owner's name, the recipient's account owner's name, and the transfer amount.
  • If both accounts exist, it calls the transfer method on the sender's BankAccount object, passing the recipient's BankAccount object and the transfer amount as arguments.
• Option 6: Exit
  • Exits the program with a goodbye message.
• Invalid Option
  • Prints an error message if the user enters an invalid menu option.