C++ Interview Questions (Fresher)

Top 30+ C++ Interview Questions for Freshers with Detailed Answers

Searching for the most relevant C++ interview questions for freshers? This comprehensive list includes frequently asked questions covering basic to advanced C++ concepts. Whether you are preparing for coding interviews or written tests, these C++ interview questions for freshers will help you build confidence and sharpen your programming skills in C++.

Easy C++ Interview Questions for Freshers

1. What is C++?

C++ is a high-level, general-purpose programming language that supports procedural, object-oriented, and generic programming paradigms. It is an extension of the C language with additional features.

2. What are the basic data types in C++?

The basic data types in C++ include int, char, float, double, bool, and void.

3. What is the difference between C and C++?

C++ supports object-oriented programming with classes and objects, whereas C is procedural. C++ also includes features like function overloading, templates, and exception handling.

4. What is a class and object in C++?

A class is a blueprint for creating objects, containing data members and member functions. An object is an instance of a class.

5. What is encapsulation?

Encapsulation is an OOP principle that binds data and methods within a class and restricts direct access to some of the object’s components to protect data integrity.

6. What are constructors and destructors?

Constructors are special member functions called when an object is created to initialize it. Destructors are called when an object is destroyed to clean up resources.

7. What is inheritance?

Inheritance allows a class (derived class) to acquire properties and behaviors from another class (base class), promoting code reuse.

8. What is polymorphism in C++?

Polymorphism allows functions or methods to behave differently based on the object that calls them, primarily achieved via function overloading and overriding.

9. What is the difference between function overloading and overriding?

Overloading allows multiple functions with the same name but different parameters within the same class. Overriding means redefining a base class method in a derived class.

10. What is a pointer in C++?

A pointer is a variable that stores the memory address of another variable.

11. What is the difference between pointer and reference?

A pointer can be reassigned and can point to NULL, while a reference is an alias for an existing variable and must be initialized when declared.

12. What are access specifiers in C++?

Access specifiers control the accessibility of class members: public, private, and protected.

Medium C++ Interview Questions for Freshers

13. What is virtual function?

A virtual function is a member function in a base class that can be overridden in a derived class to achieve runtime polymorphism.

14. What is the difference between new and malloc?

new initializes objects and calls constructors, returns typed pointer; malloc allocates raw memory and returns void pointer without initialization.

15. What is a template in C++?

Templates enable writing generic functions or classes to work with any data type without rewriting code for each type.

16. What are inline functions?

Inline functions suggest the compiler to insert function code directly at the call site to reduce overhead of function calls.

17. Explain exception handling in C++.

Exception handling uses try, catch, and throw blocks to handle runtime errors gracefully.

18. What is the difference between shallow copy and deep copy?

Shallow copy copies object references, leading to shared data, while deep copy duplicates the actual data, making independent copies.

19. What is RAII?

RAII (Resource Acquisition Is Initialization) ties resource management to object lifetime, releasing resources in destructors to prevent leaks.

20. What is the difference between stack and heap memory?

Stack stores function variables and follows LIFO; heap is used for dynamic memory allocation managed via pointers.

21. What is operator overloading?

Operator overloading allows defining custom behavior for operators (like +, -, etc.) when used with user-defined types.

22. What are smart pointers?

Smart pointers (like unique_ptr, shared_ptr) automate memory management by automatically deleting objects when no longer used.

Advanced Questions for Freshers

23. What is the difference between virtual inheritance and normal inheritance?

Virtual inheritance avoids multiple “diamond problem” instances by sharing a single base class copy in multiple inheritance scenarios.

24. Explain the concept of move semantics in C++11.

Move semantics allow resources to be transferred from temporary objects rather than copied, improving performance by avoiding deep copies.

25. What are lambda expressions in C++?

Lambdas are anonymous functions introduced in C++11 used for inline function definitions, often for short, concise code.

26. What is the difference between an abstract class and interface in C++?

C++ has abstract classes with at least one pure virtual function; unlike Java, there’s no separate interface keyword, but interfaces are modeled via abstract classes.

27. What is the difference between const pointer and pointer to const?

A const pointer cannot point to a different address, but data pointed to can be modified. Pointer to const cannot modify the data but can point elsewhere.

28. What are friend functions and friend classes?

Friend functions/classes can access private and protected members of another class, useful for operator overloading and certain class interactions.

29. What is the Standard Template Library (STL)?

STL is a collection of template classes and functions providing data structures (vector, list, map) and algorithms (sort, search).

30. Explain differences between references and pointers in C++.

References must be initialized once and cannot be null or changed; pointers can be reassigned, can be null, and require dereferencing.

31. How is memory managed in C++?

C++ supports both automatic (stack) and dynamic (heap) memory management, but dynamic allocation requires explicit deallocation via delete.

32. What is multiple inheritance? What are its challenges?

Multiple inheritance allows a class to inherit from multiple base classes but can cause ambiguity and the diamond problem.

These C++ interview questions for freshers provide a solid foundation and prepare you for entry-level interviews with confidence.