Hackerrank Object-Oriented Programming Basics 4

Question 1

What is the purpose of the @property decorator?

Accepted Answer

It makes an attribute read-only by default and allows controlled access via a method

Answer

It converts a class method into an instance method

Answer

It marks a method as a static utility function

Answer

It prevents a method from being inherited

Question 2

What does 'polymorphism' mean in the context of Python OOP?

Accepted Answer

Different classes can define the same method name with different behavior

Answer

A class can only have one shape of data

Answer

An object can change its class at runtime

Answer

A function can accept only one type of argument

Question 3

Which naming convention indicates a 'protected' attribute in Python?

Accepted Answer

_attribute (single underscore)

Answer

__attribute (double underscore)

Answer

attribute_ (trailing underscore)

Answer

ATTRIBUTE (all caps)

Question 4

What is name mangling in Python?

Accepted Answer

Double-underscore prefix causes Python to rewrite the attribute name to _ClassName__attr

Answer

Renaming a method when it is inherited

Answer

Converting attribute names to lowercase at runtime

Answer

Deleting attributes that are not used

Question 5

What will this print?
class Animal:
    def speak(self):
        return 'Generic'
class Cat(Animal):
    def speak(self):
        return 'Meow'
print(Cat().speak())

Accepted Answer

Meow

Answer

Generic

Answer

None

Answer

AttributeError

Question 6

What is an abstract class in Python, and how is it created?

Accepted Answer

A class that cannot be instantiated and may define abstract methods; created using abc.ABC

Answer

A class with no methods; created with class Empty: pass

Answer

A class whose attributes are all class-level; created with @classmethod on every method

Answer

A class that can only be used inside another class; created with a nested class definition

Question 7

What does __repr__ return compared to __str__?

Accepted Answer

__repr__ returns an unambiguous developer-oriented string; __str__ returns a user-friendly string

Answer

__repr__ returns a formatted display string; __str__ returns the raw memory address

Answer

__repr__ is called by print(); __str__ is called by repr()

Answer

They return identical strings in all cases