Exercise 10-14:
Observe the withdrawal method from the Account and SpecialAccount classes. Modify the withdrawal method of the Account class so that the possibility of withdrawal is verified by a new method, replacing the current condition. This new method should return True if the withdrawal can be performed or False if not. Modify the SpecialAccount class to work with this new method. Check whether you need to change the SpecialAccount withdrawal method or just the new method created to verify the possibility of withdrawing.
Answer:
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# Python From Scratch
# Author: Nilo Ney Coutinho Menezes
# Editora Novatec (c) 2010-2025 - LogiKraft 2025
# Site: https://pythonfromscratch.com
# ISBN: 978-85-7522-949-1 (Paperback), 978-85-7522-950-7 (hardcover), 978-85-7522-951-4 (ebook)
#
# File: chapter 10/exercise-10-14.py.py
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# Here accounts.py and clients.py were copied into a single file.
# This change is only to facilitate the visualization
# of the answer to this exercise.
class Client:
def __init__(self, name, phone):
self.name = name
self.phone = phone
# Modify the accounts.py file from the listings
class Account:
def __init__(self, clients, number, balance=0):
self.balance = 0
self.clients = clients
self.number = number
self.operations = []
self.deposit(balance)
def summary(self):
print(f"AC N°{self.number} Balance: {self.balance:10.2f}")
def can_withdraw(self, value):
return self.balance >= value
def withdraw(self, value):
if self.can_withdraw(value):
self.balance -= value
self.operations.append(["WITHDRAW", value])
return True
else:
print("Insufficient balance!")
return False
def deposit(self, value):
self.balance += value
self.operations.append(["DEPOSIT", value])
def statement(self):
print(f"Statement AC N° {self.number}\n")
for o in self.operations:
print(f"{o[0]:10s} {o[1]:10.2f}")
print(f"\n Balance: {self.balance:10.2f}\n")
class SpecialAccount(Account):
def __init__(self, clients, number, balance=0, limit=0):
Account.__init__(self, clients, number, balance)
self.limit = limit
def can_withdraw(self, value):
return self.balance + self.limit >= value
def statement(self):
Account.statement(self)
print(f"\n Limit: {self.limit:10.2f}\n")
print(f"\n Available: {self.limit + self.balance:%10.2f}\n")
# Note that with the can_withdraw method of SpecialAccount
# we don't even need to write a special withdraw method!
joe = Client("Joe", "1243-3321")
account = SpecialAccount([joe], 3432, 5000, 1000)
account.statement()
account.withdraw(6000)
account.withdraw(3000)
account.withdraw(1000)
account.statement()