C++ Classes and Objects MCQ

Classes and objects are foundational concepts in the C++ programming language, especially when delving into Object-Oriented Programming (OOP). They help in organizing and structuring the code. How well do you know about C++ classes and objects? Let's find out with this beginner-friendly quiz!

1. What is a class in C++?

a) A data type

b) A function

c) A blueprint for creating objects

d) An instance of an object

Answer:

c) A blueprint for creating objects

Explanation:

A class in C++ defines attributes (data members) and behaviors (member functions or methods) that its objects will have. It acts as a blueprint for creating objects.

2. How do you define an object in C++?

a) classname objectname;

b) objectname classname;

c) define classname objectname;

d) class objectname;

Answer:

a) classname objectname;

Explanation:

An object is an instance of a class. It's defined using the class name followed by the object name.

3. Which among these is a valid access specifier in C++?

a) private

b) protected

c) public

d) All of the above

Answer:

d) All of the above

Explanation:

C++ supports several access specifiers, including private, protected, and public, which determine the accessibility of class members.

4. By default, members of a class are:

a) Public

b) Private

c) Protected

d) None of the above

Answer:

b) Private

Explanation:

In C++, if no access specifier is mentioned, class members are private by default.

5. What will be the output of the following code?

a) 5

b) 0

c) Compilation error

d) Undefined

Answer:

c) Compilation error

Explanation:

The member variable x is private by default and cannot be accessed directly outside the class.

6. Which among the following is a special type of function in a class?

a) Inline function

b) Virtual function

c) Constructor

d) Static function

Answer:

c) Constructor

Explanation:

A constructor is a special member function in a class that is executed whenever a new object of that class is created. It has the same name as the class.

7. How can a member function be defined outside the class?

a) By using the :: operator

b) By using the . operator

c) By using the -> operator

d) It can't be defined outside the class

Answer:

a) By using the :: operator

Explanation:

The scope resolution operator (::) is used to define a member function outside the class.

8. What is the primary purpose of a destructor?

a) To initialize the class members

b) To allocate memory for the object

c) To delete any dynamic memory allocated by the object

d) To copy the object

Answer:

c) To delete any dynamic memory allocated by the object

Explanation:

A destructor is a special member function that cleans up and releases any resources (like dynamic memory) that might have been allocated during the object's lifespan.

9. Which of the following can't have a return type?

a) Member function

b) Inline function

c) Constructor

d) Static function

Answer:

c) Constructor

Explanation:

Constructors don't have a return type, not even void.

10. A class can have:

a) Only one constructor

b) Only two constructors

c) As many constructors as needed

d) No constructors

Answer:

c) As many constructors as needed

Explanation:

A class can have multiple constructors as long as they have different parameters. This is known as constructor overloading.

Kudos for taking the C++ Classes and Objects quiz! Classes and objects are essential when working with C++, and understanding them is crucial for deeper dives into OOP. Whether you aced the quiz or learned something new, remember that practice makes perfect. Dive deeper into the topic and continue expanding your C++ knowledge!