Cplusplus interview questions help you prepare for the interviews lined up ahead and will keep you ahead of the other candidates applying for the same role. If you are looking for a successful career as a developer then you need to be proficient in one of the high level programming languages like C++.
While practice is one of the most important aspects to prepare for interviews or upskilling in a particular language. It is also important that we keep updating our mind directories. In this blog, let us learn more about Cplusplus interview questions for beginners as well as professionals.
10 Cplusplus Interview Questions With Solution For Beginners
Let us get an overview around some of the basic Cplusplus interview questions for beginners along with the solutions.
1. What is the basic difference between C and C++ language?
Ans: C language is a procedural language while C++ is a procedural language along with object oriented programming support. C++ supports classes and objects, while C does not
2. What are the basic data types in C++ language?
Ans: Some of the basic data types used in C++ programming are mentioned below.
- int
- float
- double
- char
- bool
- void
3. What is C++ language?
Ans: A class in C++ language is a user defined data type that holds variables and methods i,e. Functions. Let us get the concept of class with a simple example below.
| class Car {
public: string brand; void start() { cout << “Car started\n”; } }; |
4. What is Object in C++?
Ans: Object in Object oriented Programming is an instance of the class which contains a unique value for an entity.
| Car myCar; // myCar is an object of class Car |
5. What is Inheritance?
Ans: In C++ inheritance is a process in which one class i,e. Derived class inherits the attributes and methods from the parent class i,e. Base class. This help in making the code reusable by establishing a hierarchical relationship between classes.
| class Animal {
public: void eat() { cout << “Eating\n”; } }; class Dog : public Animal { public: void bark() { cout << “Barking\n”; } }; |
6. What is Polymorphism?
Ans: Polymorphism means “many forms.” It allows functions or methods to act differently based on the object that calls them.
7. What is Encapsulation in C++ programming language?
Ans: C++ encapsulation is one of the most asked Cplusplus interview questions. It is a method by which we can bind data and methods together and keep them safe from outside reference. It works in the backend without being noticed by the users on the client side.
8. What are access specifiers in C++?
Ans: There are three types of access specifiers in C++ programming
- Public: Access to everyone
- Private: Access to members within the class only
- Protected: Access within the same class and the derived class
9. What is the difference between “==” and “=” in C++?
Ans: The double “==” sign is used to represent the equality comparison operator while the single “=” sign is an assignment operator used to assign values to the variables.
10. What is this pointer in C++?
Ans: “this” pointer in C++ refers to the current object in a porgram. This is one of the most confusing and frequently asked in Cplusplus interview questions.
30 Cplusplus Interview Questions For Freshers
Let us list all important Cplusplus interview questions for freshers in 2025, try it yourself and find the answers to ace your interview rounds.
- What is C++ and how is it different from C?
- What are the basic data types in C++?
- What is the difference between cin and cout?
- What is a class and how is it different from a structure?
- What is an object in C++?
- What is a constructor? List its types.
- What is a destructor?
- What is function overloading?
- What is operator overloading?
- What is the difference between public, private, and protected access specifiers?
- What is inheritance? What are its types?
- What is polymorphism?
- What is the difference between compile-time and run-time polymorphism?
- What is encapsulation?
- What is abstraction in C++?
- What is a virtual function?
- What is the use of the this pointer?
- What is the difference between call by value and call by reference?
- What is a reference variable?
- What is a pointer in C++?
- What is the difference between new and malloc()?
- What are static members in a class?
- What is the use of the const keyword?
- What is a friend function?
- What is the difference between ++i and i++?
- What is the use of the namespace keyword?
- What is the difference between a shallow copy and a deep copy?
- What are inline functions?
- What is the use of default arguments in functions?
- What is the difference between struct and class in C++?
10 Cplusplus Interview Questions For Experienced Professionals
For professionals who are already working in this role and want to make a switch to the next company can practice some major Cplusplus interview questions to get prepared for the interview.
1. What is RAII (Resource Acquisition Is Initialization)?
Ans: RAII is a C++ programming idiom where resource allocation is tied to object lifetime. Resources like memory, file handles, or sockets are acquired in a constructor and released in the destructor.
2. What is the Rule of Three/Five/Zero in C++?
Ans: Let us get a formal introduction of three/five and zero rules in C++
- Rule of Three: If a class defines any of the copy constructor, copy assignment operator, or destructor, it should define all three.
- R ule of Five: Also includes move constructor and move assignment operator.
- Rule of Zero: Prefer types that require none of these due to use of smart pointers and containers.
3. Explain the use of std::unique_ptr and std::shared_ptr.
Ans:
- unique_ptr has sole ownership of a resource.
- shared_ptr allows shared ownership using reference counting.
4. What is the difference between deep copy and shallow copy?
Ans: Shallow Copy is used to copy the address or references while Deep Copy is used to copy the actual data to make a clone. Deep copy make changes in the original value of the variable unlike shallow copy.
5. What are smart pointers in C++?
Ans: Smart pointers (unique_ptr, shared_ptr, weak_ptr) automatically manage memory, preventing memory leaks and dangling pointers.
6. What is the difference between static and const keywords?
Ans: Static keywords can be shared across all instances where it persists across functions while the const value cannot be changed once you initialise the value inside.
Read More: Top 5 C++ Internships to Apply in April 2025
7. What is placement new in C++?
Ans: Placement new constructs an object in pre-allocated memory.
| char* buffer = new char[sizeof(MyClass)];
MyClass* obj = new (buffer) MyClass(); |
8. What is a virtual function?
Ans: A function marked virtual can be overridden in derived classes, enabling polymorphism.
9. What is the vtable in C++?
Ans: The virtual table (vtable) is a mechanism used to support dynamic dispatch of virtual functions.
10. What is the “diamond problem” in C++?
Ans: Diamond problem occurs in multiple inheritance when a class inherits from two classes that inherit from the same base. It can generally be resolved using virtual inheritance.
30 Cplusplus Interview Questions For Working Professionals
Check the following list of all important Cplusplus interview questions if you are a working professional looking for a switch in other company.
- What is the Rule of Five in C++?
- Explain the differences between std::unique_ptr, std::shared_ptr, and std::weak_ptr.
- How does C++ support polymorphism? Explain with examples.
- What are the advantages of using emplace_back() over push_back() in STL containers?
- What is the difference between override and final in C++11?
- Explain how C++11 move semantics work and their benefits.
- What are rvalue references and how are they used?
- What is RAII and why is it important in C++?
- How is memory managed in C++? How do smart pointers help?
- What is the use of explicit keyword in constructors?
- Explain the concept of virtual destructors.
- What are function objects (functors) in C++?
- What are lambda expressions and how are they used?
- What is the difference between deep copy and shallow copy?
- What are template specialization and partial specialization?
- What is SFINAE and where is it used?
- Explain static and dynamic binding with examples.
- What is the virtual table (vtable) and how does it work?
- How do you avoid object slicing in C++?
- What are the advantages of constexpr in modern C++?
- How is exception safety ensured in C++ code?
- What is the difference between std::map and std::unordered_map?
- What are the differences between stack and heap memory allocation?
- How can C++ implement multiple inheritance and what are its pitfalls?
- What is the “diamond problem” in C++ and how is it resolved?
- How do you implement multithreading in C++11 and later?
- What are std::mutex and std::lock_guard used for?
- What are some C++ design patterns you’ve used in projects?
- How do you improve the performance of C++ applications?
- What tools and practices do you use for debugging and memory profiling in C++?
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Cplusplus Interview Questions FAQs
Q1. What is a C++ language?
Ans: C++ is a general-purpose, object-oriented programming language created as an extension of C. It supports classes, inheritance, polymorphism, encapsulation, and abstraction.
Q2. Does C++ language support OOPs?
Ans: Yes, C++ language is an extension of C which supports object oriented programming language along with classes, objects, polymorphism, encapsulation, and more.
Q3. How many Cpluplus interview questions is enough?
Ans: For C++ interview preparation you need a lot of practice to build your concept. There is no exact number of how many questions you exactly need. Try your best and solve as much as you can.
Q4. What is Constructor in C++?
Ans: A constructor is a special function that is automatically called when an object is created.
