Friend Functions and Friend Classes – MCQs

1. : What is a friend function in C++?
(A) A function that can access private and protected members of a class
(B) A private function inside a class
(C) A function that is always inline
(D) A member function of a class

2. : Which keyword is used to declare a friend function?
(A) private
(B) public
(C) friend
(D) external

3. : Can a friend function be a member of a class?
(A) Yes
(B) No
(C) Only if it’s static
(D) Only in inherited classes

4. : Where is a friend function defined?
(A) Inside the class
(B) Outside the class
(C) Both inside and outside
(D) None of the above

5. : Can friend functions access private data members of a class?
(A) Yes
(B) No
(C) Only public members
(D) Only static members

6. : Which of the following is true about friend functions?
(A) They are inherited
(B) They can be called using class objects
(C) They do not require object to be called
(D) They can access only static members

7. : Can a friend function be declared as virtual?
(A) Yes
(B) No
(C) Only for derived classes
(D) Only if static

8. : What is a friend class?
(A) A class that inherits another class
(B) A class that shares its private members with another class
(C) A class that cannot be instantiated
(D) A class that contains only friend functions

9. : Which keyword is used to declare a friend class?
(A) private
(B) protected
(C) share
(D) friend

10. : What can a friend class access?
(A) Only public members
(B) All members including private and protected
(C) Only static members
(D) None

11. : Can a friend function be overloaded?
(A) Yes
(B) No
(C) Only once
(D) Only if private

12. : Are friend functions inline by default?
(A) Yes
(B) No
(C) Only static ones
(D) Only for constructors

13. : Can a friend function access protected members of a class?
(A) Yes
(B) No
(C) Only in derived classes
(D) Only if declared inline

14. : How is a friend function different from a member function?
(A) It is defined inside the class
(B) It is defined outside the class and not a member
(C) It uses the this pointer
(D) It is called using object name

15. : Can a friend function of one class be a member of another class?
(A) Yes
(B) No
(C) Only in templates
(D) Only static ones

16. : Can a friend function be a global function?
(A) Yes
(B) No
(C) Only within main()
(D) Only if virtual

17. : Which access modifier is used with friend functions?
(A) friend
(B) Any (public, protected, or private)
(C) Only public
(D) Only private

18. : What is required for a function to be a friend function of a class?
(A) It must be declared in the class using the friend keyword
(B) It must be a class member
(C) It must be private
(D) It must be virtual

19. : Can a class declare another class as a friend more than once?
(A) Yes
(B) No
(C) Only in public scope
(D) Only if inherited

20. : Are friend functions inherited in derived classes?
(A) Yes
(B) No
(C) Only virtual ones
(D) Only private ones

21. : Can a function be friend to more than one class?
(A) Yes
(B) No
(C) Only if static
(D) Only if member of another class

22. : Can a friend function be declared in multiple classes?
(A) Yes
(B) No
(C) Only once globally
(D) Only for abstract classes

23. : What kind of relationship does a friend function violate in OOP?
(A) Encapsulation
(B) Inheritance
(C) Polymorphism
(D) Abstraction

24. : Can a friend function be a template function?
(A) Yes
(B) No
(C) Only for static classes
(D) Only for constructors

25. : How many friend classes can a class have?
(A) 1
(B) 10
(C) As many as needed
(D) None

26. : Where is the friend function prototype written?
(A) Inside class definition
(B) Inside main()
(C) Inside another class
(D) In a namespace

27. : How can a friend function be called?
(A) Using class name
(B) Using object
(C) Like a normal function
(D) It is called automatically

28. : What is one major drawback of friend functions?
(A) Cannot access static members
(B) Cannot be inline
(C) Violates encapsulation
(D) Cannot be overloaded

29. : What is the scope of a friend function?
(A) Limited to class
(B) Global
(C) Local
(D) Public only

30. : What is needed to allow a function from one class to access private members of another?
(A) Declare the function as static
(B) Declare the function as inline
(C) Declare it as friend in the target class
(D) Make it protected