Chapter 8: MCQs on Basic Object-Oriented Programming Concepts in C++ | C++ Programming
Explore fundamental concepts of Object-Oriented Programming (OOP) with these 30 MCQs. Topics include classes and objects, constructors and destructors, access modifiers, and encapsulation in C++. Perfect for mastering core OOP principles.
MCQs on Basic Object-Oriented Programming (OOP) Concepts
Classes and Objects
- What is a class in C++?
- a) A variable type
- b) A blueprint for creating objects
- c) A data structure used for functions
- d) A type of loop
- Which of the following statements is true about objects?
- a) Objects are a blueprint of classes
- b) Objects are instances of classes
- c) Objects do not have attributes
- d) Objects only store functions
- In OOP, what does an object contain?
- a) Only data
- b) Only functions
- c) Data and functions
- d) Only public members
- Which keyword is used to define a class in C++?
- a)
object - b)
new - c)
class - d)
struct
- a)
- What is the relationship between a class and an object?
- a) Classes are instances of objects
- b) Objects are instances of classes
- c) They are the same
- d) Classes contain only functions, while objects contain data
Constructors and Destructors
- What is the purpose of a constructor in a class?
- a) To delete an object
- b) To initialize objects of a class
- c) To overload functions
- d) To define data types
- Which of the following statements is true about destructors?
- a) They are used to initialize an object
- b) They are called automatically when an object is destroyed
- c) They have parameters
- d) They cannot be defined by the user
- How many constructors can a class have in C++?
- a) Only one
- b) Only two
- c) One or more
- d) None
- When is a destructor called in C++?
- a) When an object is created
- b) When an object goes out of scope or is deleted
- c) When a function is called
- d) When a class is defined
- Which of the following correctly defines a destructor in C++?
- a)
~ClassName() - b)
ClassName::~() - c)
delete ClassName() - d)
ClassName::~ClassName()
- a)
- Can constructors be overloaded in C++?
- a) Yes, by defining multiple constructors with different parameters
- b) No, constructors cannot be overloaded
- c) Only if the class has no destructor
- d) Only if the class has no private members
- Which type of constructor is automatically called when no arguments are provided?
- a) Parameterized constructor
- b) Copy constructor
- c) Default constructor
- d) Destructor
- Which of the following statements is true about the copy constructor?
- a) It initializes an object by copying another object of the same class
- b) It destroys an object
- c) It is used to overload functions
- d) It is automatically called when an object is deleted
- What is the role of a parameterized constructor?
- a) It initializes members of an object with given arguments
- b) It only destroys an object
- c) It has no parameters
- d) It is used to initialize private members only
- What is the syntax for declaring a default constructor in C++?
- a)
ClassName() {} - b)
~ClassName() {} - c)
ClassName(void); - d)
ClassName() with default
- a)
Access Modifiers (public, private, protected)
- What is the default access modifier for class members in C++?
- a) Public
- b) Private
- c) Protected
- d) None
- Which access modifier makes a class member accessible only within its own class?
- a) Public
- b) Private
- c) Protected
- d) Friend
- If a member is declared as
public, where can it be accessed from?- a) Only within the class
- b) Within the class and its derived classes
- c) From anywhere in the program
- d) Only within the same file
- Which access modifier allows derived classes to access members but restricts outside classes?
- a) Public
- b) Private
- c) Protected
- d) Friend
- What happens if no access modifier is specified for a class member in C++?
- a) It defaults to public
- b) It defaults to private
- c) It defaults to protected
- d) It becomes inaccessible
- In a class, if you want certain methods accessible only within the same class, which modifier should you use?
- a) Public
- b) Private
- c) Protected
- d) Static
- How does the
protectedaccess modifier affect member accessibility?- a) Accessible only within the class
- b) Accessible within the class and derived classes
- c) Accessible from anywhere in the program
- d) Not accessible in any class
- Can a private member be accessed by an instance of the class?
- a) Yes, directly
- b) No, only through public methods
- c) Yes, through inheritance
- d) No, it is not accessible at all
- Which access modifier would you use to allow member access only within the same package?
- a) Public
- b) Private
- c) Protected
- d) Package
- Which of the following keywords is used to make a class accessible to other classes in the same package only?
- a)
private - b)
protected - c)
package - d)
public
- a)
Encapsulation in C++
- What is encapsulation in C++?
- a) A feature that allows inheritance
- b) A mechanism of restricting access to certain details of an object
- c) A way to write functions
- d) A process for handling multiple objects
- How is encapsulation achieved in C++?
- a) Through pointers
- b) Through classes and access modifiers
- c) Through arrays
- d) Through operator overloading
- Why is encapsulation important in OOP?
- a) It provides data hiding and security
- b) It simplifies code without providing data hiding
- c) It only focuses on function overloading
- d) It helps perform arithmetic operations
- Which of the following best describes encapsulation?
- a) Combining data and methods in a class
- b) Using only private members
- c) Using only public methods
- d) Having global variables
- Which of the following is a benefit of encapsulation?
- a) It enables data abstraction and hides details
- b) It increases code redundancy
- c) It makes data globally accessible
- d) It allows only public access
Answer Table
| Qno | Answer |
|---|---|
| 1 | b) A blueprint for creating objects |
| 2 | b) Objects are instances of classes |
| 3 | c) Data and functions |
| 4 | c) class |
| 5 | b) Objects are instances of classes |
| 6 | b) To initialize objects of a class |
| 7 | b) They are called automatically when an object is destroyed |
| 8 | c) One or more |
| 9 | b) When an object goes out of scope or is deleted |
| 10 | a) ~ClassName() |
| 11 | a) Yes, by defining multiple constructors with different parameters |
| 12 | c) Default constructor |
| 13 | a) It initializes an object by copying another object of the same class |
| 14 | a) It initializes members of an object with given arguments |
| 15 | a) ClassName() {} |
| 16 | b) Private |
| 17 | b) Private |
| 18 | c) From anywhere in the program |
| 19 | c) Protected |
| 20 | b) It defaults to private |
| 21 | b) Private |
| 22 | b) Accessible within the class and derived classes |
| 23 | b) No, only through public methods |
| 24 | d) Package |
| 25 | c) package |
| 26 | b) A mechanism of restricting access to certain details of an object |
| 27 | b) Through classes and access modifiers |
| 28 | a) It provides data hiding and security |
| 29 | a) Combining data and methods in a class |
| 30 | a) It enables data abstraction and hides details |