ExamAdept

What is the purpose of the following Python code?

class Employee:
    def __init__(self, name, __salary):
        self.name = name
        self.__salary = __salary

    @property
    def salary(self):
        return self.__salary

A:

To create a new instance of the class

B:

To define a public variable 'salary'

C:

To allow unrestricted access to the 'salary' variable

D:

To provide read-only access to the 'salary' variable

Answer: D

The @property decorator creates a read-only property 'salary', providing controlled access to the private variable '__salary'.

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How can encapsulation be enhanced in the following Python class to provide write access to the 'price' variable?

class Product:
    def __init__(self, name, price):
        self.name = name
        self.__price = price

A:

Use a double underscore prefix for 'price'

B:

Create a setter method for 'price'

C:

Make 'price' a global variable

D:

Use a single underscore prefix for 'price'

Answer: B

To provide write access to a private variable, a setter method can be created for 'price'.

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What does the following Python code demonstrate?

class Book:
    def __init__(self, title, __author):
        self.title = title
        self.__author = __author

    def get_author(self):
        return self.__author

A:

Public access specifier

B:

Private access specifier

C:

Protected access specifier

D:

Global variable

Answer: B

The double underscore prefix before 'author' indicates that it is a private variable, demonstrating encapsulation by hiding the implementation details.

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In Python, what is the primary benefit of using a property with a setter method?

class Rectangle:
    def __init__(self, width, height):
        self._width = width
        self._height = height

    @property
    def area(self):
        return self._width * self._height

    @property
    def width(self):
        return self._width

    @width.setter
    def width(self, value):
        if value > 0:
            self._width = value
        else:
            raise ValueError("Width must be greater than 0.")

A:

It allows read-only access to the width property

B:

It provides write access to the width property with validation

C:

It creates a new instance of the class

D:

It exposes all internal details of the class

Answer: B

The @width.setter decorator allows write access to the 'width' property with the provided validation in the setter method.

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

class User:
    def __init__(self, username, password):
        self.username = username
        self.__password = password

A:

Add a single underscore prefix before 'password'

B:

Add a double underscore prefix before 'password'

C:

Use a getter method for 'password'

D:

Make 'password' a global variable

Answer: B

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

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Questions for: Encapsulation