OOP – Practical Application

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. Why use OOP for a bank account?

A Groups related data and behavior together

B It's faster

2. What should __init__ set for a BankAccount?

A owner and balance

B Only the class name

3. Why check balance before withdrawing?

A Python requires it

B To prevent overdraft

4. acc.deposit(50) what should this do?

A Create a new account

B Add 50 to self.balance

5. Can one class have many objects?

A Yes each with their own data

B No only one

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1def __init__(name):		AError: balance is an attribute, not a method
2acc.balance()		BOk: Update an instance attribute in a method
3def __init__(self, name):		CValid: Constructor with self and a parameter
4self.balance += amount		DOutput: 7
5round(3.14159, 2)		EOutput: 3.14
6abs(-7)		FError: Missing self in __init__

Definitions

Encapsulation

Fill in the Blanks

Complete each line of code by filling in the missing parts.

class BankAccount: def deposit(self, amount): self._______ += amount

class TodoList: def add(self, task): self.tasks.______(task)

class BankAccount: def withdraw(self, amount): if amount <= self._______: self.balance -= amount

acc = BankAccount('Alice', 100) acc._______(50)

class Score: def ________(self): self.points = _

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A class BankAccount:

B def withdraw(self, amount):

C self.balance -= amount

Question 2

A class BankAccount:

B def deposit(self, amount):

C balance += amount

Question 3

A class TodoList:

B def __init__(self):

C tasks = []

D def add(self, task):

E self.tasks.append(task)

Question 4

A class BankAccount:

B def deposit(amount):

C self.balance += amount

Question 5

A class BankAccount:

B def __init__(self):

C self.balance = 0

D def deposit(self, amount):

E self.balance += amount

Answer Key

OOP – Practical Application

Section A: Quick Questions

A — Groups related data and behavior together

A — owner and balance

B — To prevent overdraft

B — Add 50 to self.balance

A — Yes each with their own data

Section B: Match the Pairs

def __init__(name): → Error: Missing self in __init__

acc.balance() → Error: balance is an attribute, not a method

def __init__(self, name): → Valid: Constructor with self and a parameter

self.balance += amount → Ok: Update an instance attribute in a method

round(3.14159, 2) → Output: 3.14

abs(-7) → Output: 7

Section C: Definitions

Encapsulation — Bundling data and methods that operate on it together in a class.~~State

Section D: Fill in the Blanks

class BankAccount:
    def deposit(self, amount):
        self.balance += amount

class TodoList:
    def add(self, task):
        self.tasks.append(task)

class BankAccount:
    def withdraw(self, amount):
        if amount <= self.balance:
            self.balance -= amount

acc = BankAccount('Alice', 100)
acc.deposit(50)

class Score:
    def __init__(self):
        self.points = 0

Section E: Spot the Error

C — No balance check could go negative. Add validation.

C — Must use self.balance balance alone is undefined here

C — tasks = [] is a local variable. Use self.tasks = [] to store on object.

B — Missing self as first parameter

E — No validation negative deposits shouldn't be allowed