Encapsulation and Data Hiding – MCQs

1. : What is the main purpose of encapsulation in object-oriented programming?
(A) To improve runtime performance
(B) To hide internal object details
(C) To reduce code readability
(D) To create public data members

2. : Which of the following is a key feature of encapsulation?
(A) Function overloading
(B) Inheritance
(C) Data hiding
(D) Polymorphism

3. : Encapsulation helps in achieving which of the following?
(A) Abstraction
(B) Compilation
(C) Memory management
(D) None of the above

4. : What access specifier is commonly used to hide data members in encapsulation?
(A) Public
(B) Protected
(C) Private
(D) Global

5. : Which concept restricts direct access to some of an object’s components?
(A) Inheritance
(B) Abstraction
(C) Encapsulation
(D) Overloading

6. : Which of the following promotes security and prevents unauthorized access?
(A) Object creation
(B) Function overloading
(C) Encapsulation
(D) Destructor

7. : What does encapsulation bind together?
(A) Only functions
(B) Only data
(C) Data and the methods that operate on that data
(D) None of the above

8. : Which principle suggests internal object details should not be exposed?
(A) Polymorphism
(B) Data hiding
(C) Function overriding
(D) Class inheritance

9. : Data members declared as private are accessible only through:
(A) Destructor
(B) Interface class
(C) Member functions
(D) Friend functions

10. : What is a benefit of data hiding in OOP?
(A) Increases dependencies
(B) Reduces security
(C) Prevents misuse of data
(D) Increases complexity

11. : Which of the following is not related to encapsulation?
(A) Reduces complexity
(B) Prevents data tampering
(C) Promotes direct data access
(D) Improves maintainability

12. : Encapsulation is implemented using:
(A) Abstract methods
(B) Access specifiers
(C) Inheritance
(D) Dynamic binding

13. : Which type of members should be used to apply encapsulation strictly?
(A) Global
(B) Public
(C) Private
(D) Static

14. : Encapsulation improves code:
(A) Compilation time
(B) Size
(C) Reusability and maintenance
(D) Execution speed

15. : Why should class fields be declared private?
(A) To increase code readability
(B) To provide better user interaction
(C) To enforce encapsulation
(D) To implement recursion

16. : Which of the following violates encapsulation?
(A) Using getters and setters
(B) Making data members public
(C) Restricting access to fields
(D) Using constructors

17. : Encapsulation ensures that:
(A) Data is always mutable
(B) Implementation details are hidden
(C) Inheritance hierarchy is clear
(D) Multiple classes cannot exist

18. : Which of the following access specifiers allows unrestricted access?
(A) Private
(B) Protected
(C) Public
(D) Secure

19. : Which access specifier supports encapsulation by restricting access to data?
(A) Public
(B) Protected
(C) Private
(D) Static

20. : What is the main objective of data hiding?
(A) To reduce memory
(B) To allow global access
(C) To safeguard data integrity
(D) To slow execution

21. : Which of these is a real-life example of encapsulation?
(A) Light switch
(B) Car engine under the hood
(C) Newspaper
(D) Whiteboard

22. : Encapsulation makes a program more:
(A) Time-consuming
(B) Reliable and manageable
(C) Dependent
(D) Complex and lengthy

23. : What is the role of getters and setters?
(A) To hide methods
(B) To manipulate private data safely
(C) To inherit from other classes
(D) To overload functions

24. : Which of the following is a violation of data hiding?
(A) Using protected members
(B) Using private methods
(C) Directly accessing class fields
(D) Using encapsulated objects

25. : Why is encapsulation important in object-oriented programming?
(A) For faster code execution
(B) For memory optimization
(C) For data security and code maintainability
(D) For adding more variables

26. : Which one is not a benefit of encapsulation?
(A) Hides complexity
(B) Promotes flexibility
(C) Increases coupling
(D) Enhances security

27. : Which one among these best supports encapsulation?
(A) Access modifiers
(B) Macros
(C) Header files
(D) Compilers

28. : A class allows access to its private members using:
(A) Interface class
(B) Getter/Setter methods
(C) Public variables
(D) Object chaining

29. : Encapsulation leads to:
(A) Increased external access
(B) More errors
(C) Well-structured and error-free code
(D) Slower execution

30. : What happens when encapsulation is ignored?
(A) Code becomes more secure
(B) Code becomes more efficient
(C) Data may be exposed and misused
(D) Classes become more portable