SOLID_3_L.py

# [Liskov Substitution Principle (LSP)] Download the python file from this link. In this file, there is an implementation of a 
# banking system for account handling. There is a savings account and a checking account class. The checking account inherits 
# the savings account as both have the same functionality and the checking account allows overdrafts (allow processing 
# transactions even if there is not sufficient balance). Redesign this program to follow the  Liskov Substitution Principle 
# (LSP) principle which represents that “objects should be replaceable by their subtypes without altering how the program 
# works”. 

from abc import abstractmethod

class Account:
    @abstractmethod
    def withdraw(self, amount):
        pass

class SavingsAccount(Account):
    def __init__(self, balance) -> None:
        self.balance = balance

    def withdraw(self, amount):
        # Savings account does not allow overdrafts
        if amount <= self.balance:
            self.balance -= amount
            print(f"Withdrew ${amount}. Remaining balance: ${self.balance}")
        else:
            print("Insufficient funds!")

class CheckingAccount(Account):
    def __init__(self, balance, overdraft_limit):
        self.balance = balance
        self.overdraft_limit = overdraft_limit

    def withdraw(self, amount):
        # Checking account allows overdrafts but with a limit
        if amount <= self.balance + self.overdraft_limit:
            self.balance -= amount
            print(f"Withdrew ${amount}. Remaining balance: ${self.balance}")
        else:
            print("Exceeds overdraft limit or insufficient funds!")

def perform_bank_actions(account):
    account.withdraw(100)
    account.withdraw(200)
    account.withdraw(500)

if __name__ == "__main__":
    # Creating instances of SavingsAccount and CheckingAccount
    savings_account = SavingsAccount(500)
    checking_account = CheckingAccount(1000, overdraft_limit=200)

    # Performing actions on both accounts
    perform_bank_actions(savings_account)
    perform_bank_actions(checking_account)