Basic Opps in C++ Interview Questions for Freshers

Safalta Expert Published by: Saksham Chauhan Updated Thu, 18 Aug 2022 02:16 AM IST


Check Basic Opps in C++ Interview Questions for Freshers Here At

Every interview you go to will ask you about Object-Oriented Programming because it is one of the fundamental ideas in the programming field. The most frequently asked OOPs interview questions for new hires are compiled in this article to assist you ace your interviews. Therefore, start preparing.
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What is Object Oriented Programming?

Ans. Programming that is based on objects rather than just functions and processes is known as object-oriented programming (OOPs). Classes are used to categorise individual items.

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OOPs incorporates real-world concepts like polymorphism, inheritance, hiding, etc. into programming. Additionally, it             enables the connection of code and data.

2. How do access modifiers work?

Ans. To specify accessibility for class members, utilise access modifiers. It specifies how to gain access to class members outside of the confines of the class.
         Three categories of access modifiers exist:
  • Private
  • Public
  • Protected
3. What is the int data type's size?

Ans. The integer data type is 4 bytes in size.

4. Which operator from the list below can never be overloaded?

Ans. Overloading the ?: operator is not feasible due to syntactical constraints.

5. Which one of these is used to return the string's length in characters?

Ans: The character count in the string is returned using size and length.

6. Can software be built without the primary function?

Ans: The main() function is the entry point, from which all execution starts, thus while a programme can be compiled without it, it cannot be started or executed. You can run the application even without the entry point.

7. What in C++ is std?

Ans:  In C++, the standard namespace is std.

8. Describe a superclass.

Ans: A class that serves as a parent to another class or classes is known as a superclass or base class. For instance, the class Car is a superclass of the class Vehicle.

9. Describe a subclass.

Ans: A subclass is a class that derives from another class. For instance, the class Car is a descendant or subclass of the class Vehicle. 

10. What distinguishes C and C++ from each other?

C C++

C is a procedure-oriented programming language

C++ is a partially object-oriented programming language

It follows a top-down approach

It follows a bottom-up approach

C doesn’t support function or operator overloading

C++ supports function as well as function overloading

C language doesn’t support virtual and friend function

C++ language supports both virtual and friend functions.

C language has 32 keywords 

C++ language contains 52 keywords

11. Difference between the assignment operator (=) and equal to

Ans: The equals sign (==) determines if two values are equal. If equal, it will return true; otherwise, it will. The left operand receives the value of the right-side expression when the assignment operator = is used.

12. What is encapsulation?

Ans: Encapsulation is the process of combining the programming that manipulates the data and the data itself into a single entity. a class, as an illustration. Since the data supplied in one class is concealed from other classes through encapsulation, data hiding is also possible.

13. What do C++ destructors do?

Ans: When an object is destroyed in C++, a deconstructor (function) is immediately invoked. It shares the constructor's name but comes before it with a tilde. Memory is deallocated and cleaning is done by destructors.

14. What does C++ OOPs mean?

  • Object
  • Class
  • Inheritance
  • Polymorphism                                       
  • Encapsulation
  • Abstraction
15. In C++, what are pointers?

Ans: Pointers are variables that keep track of another variable's memory address. The type of the variable and the type of the pointer must match.

         Syntax: type *name

16. An inline function is what?

Ans: When invoked, an inline function extends in line. The whole code of the inline function is added or replaced at the inline function call when you call this function.


 Inline return-type function-name(parameters)



17. Compare and contrast new with malloc.

new malloc

new is an operator

malloc() is a function

It calls the constructor

The malloc function doesn’t call the constructor

There is no need to specify memory size while using new()

You have to specify the memory size

new operator can be overloaded

malloc() can never be overloaded

18. A last variable is what?

Ans: A variable that has a constant value. By virtue of the non-transversality feature, it always refers to the same item.

19. A copy function Object() { [native code] }: what is it?

Ans: A copy function Object() { [native code] } is a member function that uses another object from the same class to initialise a new object. Both the default copy function Object() { [native code] } and the user-defined copy function Object() { [native code] } are types of this function Object() { [native code]           }.

20. What is Abstraction?

Ans: Abstraction is a method that allows you to hide internal information or implementation details while just displaying to the user the functionality you want them to see.

21. A finally block is what?

Ans: Code that is used to execute crucial code, such as shutting a connection, etc., is contained in a finally block. When the try block exits, this block starts to run. Additionally, it ensures that the finally block is executed even if an unanticipated exception arises.

22. What distinguishes virtual functions from pure virtual functions?

Ans: Virtual function: A base class member function that has been modified for use in a derived class. With a virtual keyword, it is declared.

         Pure virtual function: An unimplemented function. It is established by allocating 0. There is no body to it.

23. In C++, how may you deallocate and allocate memory?

Ans: In C++, use the new operator to allocate memory and the delete operator to deallocate it.

24. What is a try/ catch block?

Ans: To deal with exceptions, a try/catch block is utilised. A series of statements that might result in an error are defined by the try block. In essence, the catch block catches the exception.

25. What distinguishes an exception from an error?


Error: Errors are issues that apps shouldn't experience.
Exception: Conditions that a programme may attempt to catch

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