ExamAdept

In Python, what is the benefit of using a private variable with a double underscore prefix, such as __song_count?

class MusicLibrary:
    __song_count = 0

    def update_count(self, count):
        MusicLibrary.__song_count += count

A:

It improves code maintainability by hiding implementation details

B:

It allows unrestricted access to __song_count

C:

It exposes all internal details of __song_count

D:

It creates a global variable

Answer: A

Encapsulation with a double underscore prefix improves code maintainability by hiding the implementation details of the class attribute __song_count.

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Consider the following Python code:

class Square:
    def __init__(self, __side_length):
        self.__side_length = __side_length

    def calculate_area(self):
        return self.__side_length ** 2

What is the purpose of the calculate_area() method?

A:

To retrieve the area of the square

B:

To set a new area for the square

C:

To calculate the area of the square

D:

To expose all internal details of the class

Answer: C

The calculate_area() method calculates and returns the area of the square, demonstrating encapsulation.

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How can encapsulation be enforced in Python to make a variable 'reservation_code' accessible only within its own class?

class Reservation:
    def __init__(self, reservation_code, __status):
        self.reservation_code = reservation_code
        self.__status = __status

A:

Use a getter method for 'reservation_code'

B:

Add a single underscore prefix before 'reservation_code'

C:

Make 'reservation_code' a global variable

D:

Add a double underscore prefix before 'reservation_code'

Answer: D

Adding a double underscore prefix before 'reservation_code' makes it a private variable, enforcing encapsulation within the class.

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What is the primary purpose of the following Python class?

class Person:
    def __init__(self, name, __age):
        self.name = name
        self.__age = __age

    def get_age(self):
        return self.__age

A:

To create a new instance of the class

B:

To provide controlled access to the 'age' variable

C:

To define a public variable 'age'

D:

To allow unrestricted access to the 'age' variable

Answer: B

The get_age() method provides controlled and read-only access to the private variable '__age', demonstrating encapsulation.

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In Python, what is the benefit of using a private variable with a double underscore prefix, such as __stock_quantity?

class Inventory:
    __stock_quantity = 0

    def update_stock(self, quantity):
        Inventory.__stock_quantity += quantity

A:

It improves code maintainability by hiding implementation details

B:

It allows unrestricted access to __stock_quantity

C:

It exposes all internal details of __stock_quantity

D:

It creates a global variable

Answer: A

Encapsulation with a double underscore prefix improves code maintainability by hiding the implementation details of the class attribute __stock_quantity.

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Questions for: Encapsulation