C++ is a powerful programming language behind operating systems, games, browsers, and real-time systems. It was created by Bjarne Stroustrup in 1979 as an extension of C to add object-oriented features. Thanks to its speed and flexibility, C++ is still a must-have skill for developers in the IT sector. That’s why you will often find C++ questions appearing in technical interviews. So, to make your preparation easier, we have put together 50+ commonly asked C++ interview questions with simple answers. You will also find quick tips to help you feel more confident before the big day.
Fun Fact – C++ powers major platforms like Google Chrome, Adobe Photoshop, Amazon, and parts of Facebook’s back-end systems.
Note – We have grouped C++ top interview questions into basic, freshers, experienced, advanced, technical, coding, and MCQs for easy preparation.
Basic C++ Interview Questions
Here is a list of basic interview questions in C++ to help you strengthen your core concepts before your interview.
- What is C++?
C++ is a high-performance programming language used for building software like operating systems, games, and real-time applications. It supports both procedural and object-oriented programming, making it powerful, flexible, and widely used even today across many industries.
- What is the difference between C++ and C?
C++ and C are closely related but serve different purposes in programming. The table below highlights the key differences between them.
| Aspect | C | C++ |
| Programming Style | Procedural programming | Object-oriented programming |
| Key Features | Functions, structured programming | Classes, inheritance, polymorphism |
| Usage | System programming, low-level tasks | Application development, real-time systems |
| Focus | Efficiency and direct hardware access | Abstraction, code reuse, flexibility |
| Relationship | Original base language | Extension of C with added features |
- What are the basic data types supported in C++?
C++ supports int, float, double, char, bool, and void. It also includes derived types like arrays, pointers, and references. The language has advanced types like enums and structs too.
- Explain the concept of object-oriented programming in C++.
Object-oriented programming (OOP) in C++ organizes code into objects. Objects combine data and functions. Key principles include encapsulation, inheritance, abstraction, and polymorphism.
- What is a constructor? How is it different from a method?
A constructor initializes an object when it’s created. It has the same name as the class. Unlike methods, constructors do not return any value, not even void.
- What is the difference between call by value and call by reference in C++?
Call by value copies the actual value. Changes inside the function do not affect the original variable. Call by reference passes the address, allowing the function to modify the original value.
Note – Basic C++ questions asked in interview often cover concepts like syntax, data types, OOP basics, and simple programs.
C++ Interview Questions for Freshers
Here are commonly asked C++ interview questions and answers for freshers and entry-level developers.
- What are the main features of C++ as a programming language?
C++ offers features like,
- Object-oriented programming (OOP)
- Strong type checking
- Low-level memory access
- Fast execution speed
- Support for procedural and OOP styles
- Function overloading
- Inheritance and polymorphism
- Templates and generic programming
- Efficient memory management
- What is function overloading in C++?
Function overloading allows multiple functions with the same name but different parameters. It helps in writing cleaner and more readable code.
- How is encapsulation achieved in C++?
Encapsulation is achieved by keeping data private and providing public methods to access and modify it. This hides internal details from outside code.
- What is the use of the “this” pointer in C++?
The “this” pointer holds the address of the current object. It is mainly used to resolve conflicts between class attributes and method parameters.
- What are access specifiers in C++? Name them.
Access specifiers define how class members are accessed. They are public, private, and protected. Each controls visibility differently.
- What is the difference between a class and a structure in C++?
In C++, classes have private members by default, while structures have public members. Otherwise, they behave similarly, supporting functions and access control.
Note – These Cpp interview questions and answers for freshers cover the basics you must know before moving to advanced topics.
C++ Interview Questions for Experienced
Let’s go through the important C++ interview questions and answers for experienced professionals.
- What is the Rule of Three in C++?
The Rule of Three states that if a class defines a destructor, copy constructor, or copy assignment operator, it should usually define all three. This avoids issues with resource management.
- How does virtual inheritance work in C++?
Virtual inheritance solves the “diamond problem” in multiple inheritance. It ensures that only one copy of a base class is inherited, preventing ambiguity and duplication.
- What is the purpose of the “mutable” keyword in C++?
The “mutable” keyword allows a class member to be modified even if it belongs to a const object. It’s useful for fields like internal caches.
- How do smart pointers differ from raw pointers?
Smart pointers automatically manage memory. When a smart pointer goes out of scope, it deletes the object it points to. Raw pointers need manual deletion, increasing the risk of memory leaks.
- Explain the concept of move semantics in C++11.
Move semantics allows resources to be moved instead of copied. It improves performance by transferring ownership of resources, especially when handling temporary objects.
- What C++ feature do you find most useful in large projects?
I find smart pointers extremely useful because they make memory management much safer. They also help avoid common bugs like memory leaks.
- How do you keep your C++ skills updated with the latest standards?
I regularly read official C++ documentation, follow updates on C++ standards, and practice using new features like structured bindings and constexpr if statements.
C++ Interview Questions for 3 Years Experienced
These interview questions about C++ are commonly asked to candidates with around three years of professional experience.
- What is operator overloading in C++?
- Describe a situation where you debugged a complex C++ application.
- What C++ features do you enjoy working with the most, and why?
- How would you manage memory in a C++ project with frequent dynamic allocations?
C++ Interview Questions for 5 Years Experienced
These C++ language interview questions are designed for candidates with around five years of professional development experience.
- What is the difference between shallow copy and deep copy?
- Tell us about a C++ project where you improved performance significantly.
- Which C++ version features (C++11, C++14, C++17) have you used the most?
- How would you handle thread synchronization in a multithreaded C++ application?
C++ Interview Questions for 7 Years Experienced
Here are C Plus Plus interview questions for candidates with around seven years of industry experience in C++ development.
- What is a virtual destructor, and when is it needed?
- Describe a situation where you had to refactor legacy C++ code.
- How do you stay updated with changes in the C++ language?
- How would you design a thread-safe singleton in C++?
C++ Interview Questions for 10 Years Experienced
These Cpp interview questions are suitable for candidates with around ten years of experience in C++ development and system design.
- What is the importance of RAII (Resource Acquisition Is Initialization) in C++?
- Share a challenge you faced while optimizing a large C++ system.
- What architectural patterns do you prefer when designing C++ applications?
- How would you debug a memory leak in a high-availability C++ service?
Advanced C++ Interview Questions
Here are some frequently asked advanced C++ interview questions answers to help you prepare for senior-level technical interviews.
- What is SFINAE (Substitution Failure Is Not An Error) in C++ templates?
SFINAE allows the compiler to discard invalid template instantiations without producing an error. It helps in selecting the correct overloads during template specialization.
- Explain covariance and contravariance in C++ with examples.
Covariance means a derived class return type is allowed when overriding a base class function. Contravariance with parameters is not directly supported in C++, unlike some other languages.
- How does constexpr differ from const in C++?
const means a variable cannot change after initialization. constexpr means the value must be known and evaluated at compile-time. It is useful for optimization and better type safety.
- What are perfect forwarding and its use cases in C++11 and above?
Perfect forwarding passes arguments to another function exactly as received. It keeps lvalues as lvalues and rvalues as rvalues. It is mainly used in factory functions and wrapper templates.
Note – Advanced Cpp questions for interview include topics like memory management, multithreading, design patterns, and complex problem-solving.
C++ Technical Interview Questions
Let’s go through the important technical C++ interview questions and answers to help you prepare for real-world coding interviews.
- What happens internally when you create an object in C++?
Memory is allocated on the stack or heap. Then, the constructor is called to initialize the object’s data members.
- How does dynamic polymorphism work under the hood in C++?
Dynamic polymorphism uses a vtable (virtual table) mechanism. A vtable holds pointers to virtual functions. At runtime, the correct function is called through the vtable.
- What are the common causes of segmentation faults in C++ programs?
Segmentation faults happen due to invalid memory access. Common reasons include dereferencing null pointers, accessing out-of-bounds arrays, or using dangling pointers.
- How would you handle exception safety in C++ applications?
I use RAII (Resource Acquisition Is Initialization) to tie resources to object lifetimes. I also write strong exception-safe code where possible and avoid manual resource management.
Note – Technical interview questions about C++ are often asked for roles like software developer, systems engineer, game developer, and backend engineer.
C++ Coding Interview Questions
Here is a list of common C++ programming interview questions focused on coding skills and problem-solving techniques.
- Write a program to reverse a linked list in C++.
struct Node {
int data;
Node* next;
};
Node* reverseList(Node* head) {
Node* prev = nullptr;
Node* curr = head;
while (curr) {
Node* nextNode = curr->next;
curr->next = prev;
prev = curr;
curr = nextNode;
}
return prev;
}
- Implement a stack using two queues in C++.
#include <queue>
class Stack {
std::queue<int> q1, q2;
public:
void push(int x) {
q1.push(x);
}
int pop() {
while (q1.size() > 1) {
q2.push(q1.front());
q1.pop();
}
int top = q1.front();
q1.pop();
std::swap(q1, q2);
return top;
}
};
- Write a function to detect a loop in a linked list.
bool hasLoop(Node* head) {
Node* slow = head;
Node* fast = head;
while (fast && fast->next) {
slow = slow->next;
fast = fast->next->next;
if (slow == fast)
return true;
}
return false;
}
- Implement binary search using recursion in C++.
int binarySearch(int arr[], int left, int right, int target) {
if (left > right)
return -1;
int mid = left + (right – left) / 2;
if (arr[mid] == target)
return mid;
else if (arr[mid] > target)
return binarySearch(arr, left, mid – 1, target);
else
return binarySearch(arr, mid + 1, right, target);
}
- Write a program to find the largest subarray sum (Kadane’s algorithm).
int maxSubArraySum(int arr[], int n) {
int maxSum = arr[0], currentSum = arr[0];
for (int i = 1; i < n; ++i) {
currentSum = std::max(arr[i], currentSum + arr[i]);
maxSum = std::max(maxSum, currentSum);
}
return maxSum;
}
C++ Interview Questions MCQ
This section covers Cpp interview questions and answers in MCQ format to help you test and improve your C++ knowledge.
- Which of the following is not a type of constructor in C++?
- A) Default constructor
- B) Copy constructor
- C) Move constructor
- D) Virtual constructor
Answer: D) Virtual constructor
- What is the output of sizeof(char) in C++?
- A) 1
- B) 2
- C) 4
- D) 8
Answer: A) 1
- Which operator cannot be overloaded in C++?
- A) +
- B) []
- C) ::
- D) ()
Answer: C) ::
- What is the default access specifier for a class member in C++?
- A) Public
- B) Private
- C) Protected
- D) Friend
Answer: B) Private
- Which C++ feature allows a function to have different meanings based on the argument types?
- A) Inheritance
- B) Function Overloading
- C) Templates
- D) Encapsulation
Answer: B) Function Overloading
- Which of the following containers stores elements in sorted order in C++ STL?
- A) vector
- B) map
- C) unordered_map
- D) stack
Answer: B) map
- What is the keyword used to create an object on the heap in C++?
- A) malloc
- B) allocate
- C) new
- D) create
Answer: C) new
- Which function is called automatically when an object goes out of scope?
- A) Constructor
- B) Destructor
- C) Virtual function
- D) Friend function
Answer: B) Destructor
Other C++ Important Interview Questions
We have covered the main C++ interview questions. Now, here are a few more important ones to sharpen your preparation.
C++ Tricky Interview Questions
This section includes tricky C Plus Plus interview questions to test your deep understanding and problem-solving skills.
- What happens if a base class pointer points to a derived class object without a virtual destructor?
- Can you overload the main() function in C++?
- Why can’t constructors be virtual in C++?
- What is the difference between delete and delete[] in C++?
- What happens if you call delete twice on the same pointer?
C++ Developer Interview Questions
These C++ developer interview questions are based on important C++ interview topics commonly asked in technical interviews.
- How do you manage memory leaks in large C++ applications?
- What is a vtable and how does it work?
- How do you implement a custom allocator in C++?
- What strategies would you use to optimize a C++ application for speed?
- What are the differences between std::vector and std::list in C++?
C++ Multithreading Interview Questions
Here are the common C++ language interview questions on multithreading.
- What is a race condition? How do you prevent it in C++?
- How does std::mutex work in C++ multithreading?
- What is the difference between a thread and a process?
- How would you implement a producer-consumer problem in C++?
- What are atomic operations in C++?
C++ STL Interview Questions
These questions on C++ interview focus on key concepts of the Standard Template Library (STL) used in real-world coding.
- What is the difference between map and unordered_map in C++ STL?
- How does std::priority_queue work internally?
- What is the time complexity of insertion in a set in C++?
- What is the difference between std::vector and std::deque?
- When should you prefer std::list over std::vector?
C++ Embedded Interview Questions
These are embedded C++ interview questions designed to test your skills in memory management, real-time systems, and low-level programming.
- How is C++ used in embedded systems development?
- What is the difference between volatile and const volatile variables in C++?
- How do you manage memory constraints in embedded C++ applications?
- What are ISR (Interrupt Service Routines) and how are they handled in embedded C++?
- How do you optimize C++ code for real-time systems?
Tips to Prepare for C++ Interview
Here are helpful C++ interview preparation tips to boost your confidence and improve your performance.
- Start by revising the basics like data types, control structures, functions, and pointers.
- Focus on key C++ interview topics such as object-oriented programming, templates, STL, memory management, and multithreading.
- Practice coding problems daily to sharpen your logical thinking and coding speed.
- Review real C++ questions asked in interview rounds by companies to understand the pattern and difficulty level.
- Build small projects using C++ to apply your knowledge practically and get hands-on practice.
- Read and understand sample C++ interview questions for different experience levels (freshers to senior developers).
- Stay updated with the latest C++ standards like C++17 and C++20 features, if possible.
- Take mock interviews or timed practice tests to simulate real interview pressure.
- Keep your answers clear and to the point during interviews to make a better impression.
Also Read - Top 20 C++ OOPs Interview Questions and Answers
Wrapping Up
And that’s a wrap on the top 50+ C++ interview questions and answers!
Preparing for interviews becomes easier when you know what to expect. Focus on building a strong understanding of core concepts, practice coding regularly, and stay confident.
If you are looking for employment opportunities, go to Hirist – an online job portal for IT professionals. Here, you can find a wide range of C++ job openings across India, including roles for freshers, experienced developers, and senior professionals.
FAQs
What is the average salary for C++ developers in India?
According to AmbitionBox, the salary of a C++ developer in India ranges from ₹2 Lakhs to ₹16.3 Lakhs for candidates with less than 1 year to 6 years of experience. Senior C++ developers with strong system-level programming skills can earn even higher.
Which top companies hire C++ developers in India?
Leading companies like Microsoft, Amazon, Qualcomm, Nvidia, Morgan Stanley, and Goldman Sachs frequently hire skilled C++ developers for roles in software development, system programming, and finance technology.
How can I prepare for the different types of questions on C++ interview?
To prepare well, focus on top C++ interview questions across different categories like basics, coding problems, advanced topics, MCQs, and real-world applications. Practice each section separately to build strong overall confidence.
How should I study C++ for interviews to perform well in coding rounds?
Focus on solving Cpp questions for interview, covering basics, object-oriented concepts, coding problems, and commonly asked technical questions.
How important is data structures knowledge for C++ interviews?
Data structures are very important for C++ interviews. Questions often test your ability to apply arrays, linked lists, trees, graphs, and dynamic programming to solve real-world problems.
Is it necessary to learn the latest C++ standards like C++17 or C++20?
While not always mandatory, knowing features from C++17 and C++20 can give you an advantage. It shows that you stay updated and can write cleaner, more efficient code.
Do freshers get C++ developer jobs easily in India?
Yes, companies hire freshers for C++ roles, especially for system programming, embedded systems, and software development. A strong understanding of basics and good coding skills can help freshers land good opportunities.
Who developed C++?
C++ was developed by Bjarne Stroustrup in 1979 at Bell Labs. He created it as an extension of the C programming language, adding features like classes and object-oriented programming.
