Computer Science Engineering Interview Questions- Basic, Core, Advanced

Interview Questions for CSE Students: What Recruiters Really Test

Technical Interview Questions for CSE: Coding & Core CS

Now, let’s look at a few technical skills and interview questions for CSE where you’re expected to think and explain clearly.

Q5. How would you detect a cycle in a linked list?

• Sample Answer: A common approach is Floyd’s Cycle Detection Algorithm, also called the tortoise and hare algorithm. I keep two pointers:
  • a slow pointer that moves one node at a time, and
  • a fast pointer that moves two nodes at a time.
  • Both start at the head. If there is no cycle, the fast pointer will eventually reach NULL and stop. If there is a cycle, at some point the fast pointer will “lap” the slow pointer, meaning both pointers will point to the same node.
  • This algorithm works in O(n) time and O(1) extra space, which makes it efficient and widely used in interviews.

Q6. What is a deadlock in Operating Systems? How can it be avoided?

• Sample Answer: A deadlock is a situation where a set of processes are blocked because each process is holding a resource and waiting for another resource held by someone else, forming a cycle of dependency. As a result, none of them can proceed.

  For a deadlock to occur, four conditions must hold simultaneously:

  • Mutual exclusion
  • Hold and wait
  • No pre-emption
  • Circular wait
• To avoid deadlock, we can break at least one of these conditions. For example:
  • Use a strict resource ordering so that processes request resources in a fixed order to prevent circular wait.
  • Allow pre-emption of resources under certain conditions.
  • Make processes request all required resources at once, reducing hold-and-wait scenarios.
• In practice, systems often use a mix of deadlock prevention, avoidance, or detection and recovery, depending on the complexity and cost trade-offs.

Q7. What is an index in a database?

• Sample Answer: An index in a database is a separate data structure—often based on B-trees or hash tables—that helps the database locate rows quickly without having to scan the entire table.

  When you create an index on a column, queries that filter or join based on that column can run much faster. However, indexes come with a cost: they take extra storage and slow down write operations (INSERT, UPDATE, DELETE) because the index itself has to be updated.

  So, indexes are ideal for frequently searched columns, but we should not create them blindly on every column.

Q8. Explain encapsulation and abstraction with an example.

• Sample Answer: Encapsulation is about bundling data and the methods that operate on that data into a single unit (like a class), and restricting direct access to some of the object’s components. For example, in a BankAccount class, the balance variable is kept private, and we expose methods like deposit() and withdraw() instead.

  Abstraction is about hiding unnecessary details and showing only what is relevant. When I use a BankAccount object, I don’t need to know how the interest is calculated or how the data is stored internally; I just need to know that I can call deposit(), withdraw(), and checkBalance().

  Combined, encapsulation and abstraction make code easier to maintain, safer from misuse, and closer to real-world modeling.

Interview Questions for CSE Freshers: HR and Behavioural

Technical skills get you shortlisted; your behavioural answers decide whether the team wants to work with you. Here are some interview questions for CSE freshers with full sample answers. 

Q9. Tell me about yourself.

• Sample Answer: I’m a final-year BTech CSE student with a strong interest in backend development and databases. Over the last four years, I’ve built projects using Java, SQL, and a bit of Python, including a library management system and a REST API for a small e-commerce demo.

  I enjoy solving algorithmic problems and regularly practice on coding platforms. Recently, I completed an internship where I worked on writing APIs and optimising SQL queries, which gave me exposure to real-world codebases and teamwork.

  Right now, I’m looking for a role where I can deepen my backend development skills, work with experienced engineers, and contribute to performance-oriented applications.

Q10. What are your strengths and weaknesses?

• Sample Answer: One of my strengths is structured problem-solving. When I face an issue, I like to break it into smaller parts, write down the constraints, and then think through different approaches before coding. This has helped me a lot in debugging and DSA.

  A weakness I’ve noticed is that I sometimes take too much time polishing small parts of a project because I want them to be perfect. I’m working on this by setting clearer time limits for each task and reminding myself that iteration is better than chasing perfection in one go.

Q11. Describe a challenging project you worked on.

• Sample Answer: In my third year, I worked on a project to build a college event management web app. The main challenge was handling user registrations and sending confirmations reliably. Initially, we had issues with duplicate entries and inconsistent database states.

  I took the lead in redesigning the database schema, adding proper constraints, and using transactions to ensure consistency. I also implemented input validation on the frontend. In the end, we had a stable system that handled multiple events and users without errors, and we successfully used it in a college fest trial.

BTech CSE Interview Questions: Projects, Internships, and Skills

Companies will almost always ask project-based BTech CSE interview questions. Here’s how you can answer them in a structured way.

Q12. Explain your final-year project.

• Sample Answer: My final-year project is a movie recommendation system that suggests films based on user ratings and viewing history. The main goal was to make recommendations more personal than simple ‘top trending’ lists.

  We used a collaborative filtering approach with Python and a simple Flask backend. I was responsible for designing the database schema in MySQL and implementing the core recommendation algorithm. We evaluated the system using metrics like RMSE and also did small user feedback surveys in college.

  The project taught me how to work with real datasets, handle performance issues, and turn a theoretical idea into a working application.”

Q13. Why did you choose this tech stack for your project?

• Sample Answer: We chose Python because it has strong libraries for data analysis and machine learning, like Pandas and Scikit-learn, which made it easier to experiment with different recommendation algorithms. Flask was chosen for the backend because it is lightweight and easy to set up for a small project.

  For the database, we used MySQL since it’s reliable, familiar, and integrates well with Python. Overall, this combination allowed us to move quickly, test ideas, and still maintain a clear structure for future improvements.”

Q14. What makes you a good fit for this role?

• Sample Answer: During my BTech CSE, I’ve gained a strong foundation in DSA, OOP, and DBMS, which I apply in all my coding work. Through labs and projects, I’ve become comfortable building applications in Java and Python, using SQL for data storage, and working with Git for version control.

  Beyond technical skills, working in teams for projects and hackathons has improved my communication and collaboration. I’ve learned to break down tasks, review peers’ code, and manage deadlines—skills that I believe are essential for any software development role.

  A structured BTech CSE programme like the one at UPES is built around exactly these outcomes: strong fundamentals, hands-on projects, and industry exposure that gives you real examples to talk about in interviews. You can explore the specialisations, labs, and placement support here:

Why You Chose BTech CSE Interview Questions: Model Answers You Can Adapt

Let’s tackle one of the most common and tricky questions:

Q15. Why did you choose BTech CSE?

• Sample Answer 1 - Problem-Solving Angle: 

  I chose BTech CSE because I’ve always enjoyed solving logical problems and puzzles, and computer science felt like a field where I could turn that interest into real applications. In school, I liked mathematics and basic programming, and building small programs gave me a sense of achievement.

  CSE also gives me the chance to work on technologies that directly affect people’s lives—like apps, web platforms, or intelligent systems. During the course, projects in web development and data structures confirmed that I enjoy this work and want to grow as a software engineer.”

• Sample Answer 2 – Impact & Career Scope Angle:

  I chose BTech CSE because technology now drives almost every industry—from finance and healthcare to education and entertainment. I wanted to be in a field where my work could scale to thousands or millions of users.
  CSE offers a broad foundation, and then I can specialise later in areas like AI, cybersecurity, or data science depending on what I enjoy the most. Over the last few years, projects and coursework have shown me that I’m most interested in backend development and data, and I’d like to build my career in those directions.”
  You can mix elements from both, but keep your answer personal, clear, and honest.

Quick MCQs for CSE Interview Practice:

1. Which data structure is best if you need very fast random access?

• a) Linked list
• b) Array
• c) Queue
• d) Stack
  • Correct answer: b)

2. Which protocol is more suitable for live streaming a cricket match?

• a) TCP
• b) UDP
  • Correct answer: b)

3. In a relational database, which key uniquely identifies a record and cannot be NULL?

• a) Foreign key
• b) Primary key
• c) Candidate key
• d) Super key
  • Answer: b)

4. Which data structure is most suitable for implementing a recursion stack?

• a) Queue
• b) Linked list
• c) Stack
• d) Hash table
  • Answer: c)

5. Which HTTP method is generally used to retrieve data from a server without changing it?

• a) POST
• b) GET
• c) PUT
• d) DELETE
  • Answer: b)

Our counsellors are just a click away.

Call Me

Conclusion

Instead of memorising hundreds of cse interview questions, focus on really understanding and internalising fewer, high-impact questions—like the ones in this guide. Read the computer science engineering interview questions and answers here a couple of times, then practise saying the answers in your own words and coding the relevant problems.

Combine that with a strong foundation from your BTech CSE programme, a few solid projects, and regular coding practice, and you’ll be far more confident in front of any interviewer.

If you’re still exploring where to build that foundation, it’s worth looking at how UPES School of Computer Science structures its BTech CSE course with specialisations, industry tie-ups, and placement support that directly feed into the kind of interviews you’ve just practised for.