Python Objects and Recursion

What is recursion in Python?

• A function that calls itself
• A loop that never ends
• A built-in Python module
• A type of exception handling

Answer explanation

Recursion is a programming technique where a function calls itself to solve a problem.

Which of the following is a base case in recursion?

• A condition that stops the recursion
• A function that calls another function
• A loop that iterates indefinitely
• A recursive function without parameters

Answer explanation

The base case is a condition that stops the recursive calls and prevents infinite recursion.

What is the output of the following recursive function?
def factorial(n):
if n == 1: return 1
else: return n * factorial(n-1)

print(factorial(5))

• 120
• 24
• 6
• 1

Answer explanation

The factorial of 5 is 120, calculated as 5 * 4 * 3 * 2 * 1.

What is the main purpose of a class in Python?

• To define a blueprint for objects
• To execute a block of code
• To handle exceptions
• To create loops

Answer explanation

A class is a blueprint for creating objects, which are instances of the class.

Which keyword is used to create a class in Python?

• class
• def
• struct
• object

Answer explanation

The `class` keyword is used to define a class in Python.

What is an instance of a class?

• An object created from a class
• A method within a class
• A variable in a class
• A function outside a class

Answer explanation

An instance is an object created from a class, using the class as a blueprint.

What is the purpose of the `__init__` method in a class?

• To initialize object attributes
• To define class methods
• To create a new instance
• To handle exceptions

Answer explanation

The `__init__` method is used to initialize the attributes of an object when it is created.

What is method overriding in Python?

• Redefining a method in a subclass
• Creating a new method in a subclass
• Deleting a method from a superclass
• Calling a method from another class

Answer explanation

Method overriding occurs when a subclass provides a specific implementation of a method that is already defined in its superclass.

What is encapsulation in OOP?

• Bundling data and methods that operate on the data
• Hiding data from the user
• Creating multiple instances of a class
• Inheriting from multiple classes

Answer explanation

Encapsulation is the bundling of data and methods that operate on the data within a single unit, typically a class.

What is the purpose of the `self` keyword in Python classes?

• To refer to the instance of the class
• To define a static method
• To create a new class
• To handle exceptions

Answer explanation

The `self` keyword is used to refer to the instance of the class within the class methods.