Top C# Interview Questions: Guide and 20+ Examples from IT Pros (2023)

The problem with technical interviews is you never know if you should bring your lucky keyboard—

Or marker.

Not to mention the C# interview questions you’ll be asked are hardly predictable.

The good news?

We reached out to several C# experts to share their insights, and tell us what C# coding questions they like to ask to aspiring C# developers.

So, keep calm and read on.

This article will show you:

  • 20+ top C# interview questions.
  • Answers to help you ace the C# interview questions.
  • Advice from experienced developers, researchers, and C# experts.
  • How to answer C# coding questions so they’ll call you back.

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Top C# Interview Questions: Guide and 20+ Examples from IT Pros (1)

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (2)

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Technical questions aren’t the only ones you’ll be asked during your interview. Learn how to nail all your interview questions from our guide:


C# .NET Interview Questions

It’s no secret—

C# technical interviews usually consist of several stages.

Most of the time they start with C# phone interview questions.

The questions asked over the phone will be general coding questions, and because of the medium, focus on the more theoretical aspects of C#.

Marie Lamonde from DashThis says that potencial employees of her companyare likely to be asked the following questions:

1. Do you have any C# experience?

If not, we fall back to non-programming-language-oriented software development questions. Or questions for any other language known by the candidate. For an interview, we are looking for answers that will help us spot a great software developer. And a great software developer is not one who knows every answer Google can give you in seconds, but one who can make good design decision at the right time.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (3)

2. What are your tips to write great C# code?

(Video) OOPS Interview Questions and Answers | Object Oriented Programming Interview Questions C#

The great answers start with: Like (almost) any other language... Detailed answers circle around those: Simple and simpler, short, read like prose, do what it should, comes with great automated unit tests, use C# features to enhanced readability, etc. As a candidate, you should prepare by reading/practising about Clean Code and Clean Architecture. Practice Test-Driven development until you drop, and pair programming with people with that expertise.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (4)

In fact—

Websites such as have been specifically created to help coders hone their skills before the actual interview takes place.

3. Which C# features do you like most and why?

We're looking to grasp what the candidate really knows about the language and even more how the candidate applies this language to design/write great software. Candidates should prepare by asking themselves every day how to improve their code/design with the language features.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (5)

In other words—

You can only become a great coder (and ace your C# interview questions along the way) if coding is something you’re truly passionate about.

4. Which C# structure would you use/do to get the fastest large objects manipulation and when/why would you care?

We want to know if the candidate knows some performance tricks, and when he should care about this performance. Premature optimization is mostly a waste of time and a source of complex solutions. Candidate should learn the C# language performance tricks and really learn the ups and downs of every one of them.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (6)

It stands to logic—

The basic C# interview questions to expect in the initial screening stage won’t really require you to do coding. You’re likely to be asked about your past experience, problems you encountered, solutions you arrived at, or business contexts in which you’ve had a chance to apply your C# coding skills, etc.

Moving on to on-site C# interview questions.

The good news?

Most companies allow you to show off your coding ability in a programming language of your choice. If you’re comfortable with C#, ask for C# coding questions.

The bad news?

You never know what to expect.

You will have heard the story of Max Howell, creator of Homebrew, being rejected by Google for not being able to invert a binary tree.

(Video) Explain IEnumerable in C# ( C# Interview Questions)

We reached out to several C# experts to pick their brains on what questions they like to challenge candidates with and why.

Dzmitry Valadziankou, Lead .NET Developer at ScienceSoft, has shared his experience on interviewing C# developers.

5. What will be the output of the following code snippet?



string Name { get;set; }


T[] q =new T[100];//where T some type

INamed named = q[10];

named.Name ="bob";

Console.WriteLine(q[10].Name ??"empty");


The output of the code depends on the type of T—whether it’s the Value type or the Ref type. For the Ref type, the answer will be runtime NullRefenceException, for the Value type — null. Going further, the developer may also explain why this output is expected, cover the difference of the Value type and the Ref type as well as boxing/unboxing concepts. For extra credit, I ask them about the location of the Ref type and the Value type arrays (whether it’s stack or heap) and the speed of array element access.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (7)

6. List<T> - what is the efficiency of Add method, RemoveAt method: Add – O(1)amortize, RemoveAt – O(n)

Surprisingly, many candidates don’t know about data structures efficiency at all. Also, as the name of the class is misleading, it’s often mistaken for a LinkedList. So, if a candidate knows that this is the implementation of a dynamic array, they not just blindly use it but also look what is under the hood.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (8)

8. What is the difference between interface and abstract class?

Prior to C# 8, the abstract class could have implementation while interfaces couldn’t. In C# 8, the interface can have default implementation (saying this, a candidate shows that they are up to date). Then, I can proceed and ask what they’ll prefer when designing a class library that will be used by millions of developers and why. The answer should be that the abstract class is better as it allows adding a new method without introducing a breaking change.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (9)

(Video) Top 10 Spring MVC Interview Questions and Answers | Frequently Asked Spring MVC Interview Questions

The next set of questions comes from Somdip Dey, embedded A.I. Scientist at the University of Essex, UK. Here’s what he had to say:

8. Can you write the FizzBuzz program in C# now?

The question related to FizzBuzz seems relatively easy for some seasoned programmers but the point of asking this during an interview isn’t just to test the candidate’s coding ability. It also tests whether or not the candidate is knowledgeable about using Dictionaries and/or tuples in C#, which could drastically shorten the lines of code written in the program.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (10)

9. What are interfaces and abstract classes? And what are the differences between them? Can you give me an example?

The question about interfaces and abstract classes tests the candidate’s understanding of the object oriented paradigm. Plus, the examples are to prove whether or not they can implement interfaces and abstract classes in C#.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (11)

10. What is LINQ in C#? Have you used it in your previous programs? Give me an example.

The LINQ question tests the candidate’s competence in one of the most practically used APIs provided in .NET platform to query and retrieve data from different sources since data is center of all application workflow. I was asked about C# interfaces and abstract classes so many times during my numerous interviews with different companies that I practically wrote an article to demystify the concept.

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (12)


Christine Orchard from Codementor sent us some of the most common C# interview questions that has been identified in a piece wrote for the Codementor community:

11. What makes your code really object-oriented?

12. What are the fundamental principles of OO programming?

13. What is the this Pointer?

14. What is the OO fundamental idea using C# that allows a data structure to perform operations on its own data?

15. What is Dynamic Dispatch?

16. Why do we still see so much non-OO code written in C# today?

17. How does OO simplify development?

18. How can we use the core concepts of OO in order to make this code easy to maintain and yet still flexible enough to cope with possibly ever-changing requirements?

(Video) ASP.NET MVC Interview questions and answers on Dependency Injection | ASP.NET Interview Questions

19. How to avoid the NULL trap?

20. How to move to a State-related Codebase?

21. What is a state-related codebase?

If you don’t how to answer these C# advanced interview questions, check out the original article by Ed Freitas.

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Top C# Interview Questions: Guide and 20+ Examples from IT Pros (13)

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What Does This All Mean?

It means one thing:

If you’re serious about your C# developer career:

You’ve got a lot to learn.And then some more.

Technical interviews are the stuff legends. Some say they’ve got nothing to do with real life, and while such radical statements are arguable, one thing is certain—

They’re notoriously hard and difficult to prepare for.

For example, your C# interview questions could just as well include questions about the entire tech stack C# is part of:.NET questions, ASP.NET questions, or Entity Framework.

In fact, the Devskiller Global Technical Hiring & Skills Report 2019 shows that programming languages are often tested with other technologies in their environment.


There’s a whole thriving community of software engineers centered around helping coding newbies test their skills before the actual technical interview takes place. Check out:

To name only a few.

More than that: some companies, such as Palantir for example, publish their own guides on how to prepare for a technical interview. Google offers guidelines, too.


Code as much as you can. If you run out of ideas for apps, visit HackerRank or TopCoder to just keep coding.

Plus, a great cover letter that matches your resume will give you an advantage over other candidates. You can write it in our cover letter builder here.Here's what it may look like:

Top C# Interview Questions: Guide and 20+ Examples from IT Pros (14)

See more cover letter templates and start writing.

Key Takeaways

Here’s a quick recap of all you need to know about C# interview questions:

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  • C# interview questions are only a part of the entire technical interview.
  • Expect to be asked basic C# interview questions at the early stages of the recruitment process.
  • Your C# coding interview questions will become harder during the on-site interview.
  • You may be asked to write code live with other programmers on a shared screen, or with a marker on a whiteboard, and “think aloud.”
  • The best way to prepare yourself for C# interview questions is to:
    • practice a lot (preferably with other, more experienced developers)
    • keep challenging yourself
    • be an active member of developer communities
    • gain a broad understanding of the entire technological environment, rather than learn how to answer a number of specific questions.

Did you like the article? Do you have your own list of C# programming interview questions? Maybe you’d like to share some C# interview questions and answers? Give us a shout out in the comments below! We’d love to hear from you!


How to prepare for technical interview in C#? ›

Refine Whiteboarding Skills. Your problem-solving skills may be the lynchpin of your C# interview. As such, you should practice solving coding issues. It's best to write these out on paper so that you're used to resolving problems by hand to prepare for whiteboarding in your actual interview.

What are the 20 most common interview questions and answers for freshers? ›

Here Are 20 Of The Most Common Interview Questions and Answers For Freshers:
  • Tell Me About Yourself. ...
  • Why Should We Hire You? ...
  • What Are Your Strengths? ...
  • What Are Your Weaknesses? ...
  • What Are Your Long-term Goals? ...
  • What Are Your Short-term Goals? ...
  • How Do You Handle Stress/ Pressure? ...
  • Why Do You Want To Work Here?
Feb 28, 2022

What are the 3 C's of interview? ›

These three C's that we will examine are: Credibility; Competence; and Confidence. They are inextricably connected. I'm an introvert by personality type, but can interview with the best of them because of the successful implementation of these three C's.

What is the hardest part in C#? ›

In C#, the hardest feature is easily generic covariance and contravariance. Go here, scroll down and read the blog posts one by one from bottom to top. Make sure you understand every word of it, in particular all the examples. Warning: your brain will hurt.

What are the 7 preparations for interviews? ›

7 Steps for a Successful Interview
  • Prepare Thoroughly. Preparation goes beyond just understanding and researching the company's website and perusing the annual report; they're a given. ...
  • Make a Good First Impression. ...
  • Run Offense, Not Defense. ...
  • Use a Nonverbal Strategy. ...
  • Be Positive. ...
  • Connect All the Dots. ...
  • Ask for the Job!

What should you not do in a technical interview? ›

7 Mistakes to avoid during a technical interview
  • By Ishita Tandon. Technical interviews can be a nerve-wracking experience for candidates. ...
  • Wrong attitude. ...
  • Pretending to be know-it-all. ...
  • Not asking questions. ...
  • Forgetting the requirement. ...
  • Bad communication skills. ...
  • No enthusiasm. ...
  • Not providing enough details on what is being asked.

Is it hard to crack technical interview? ›

These interviews are a mandatory part of the recruitment process of technical experts to check their ability. However, candidates often have a hard time cracking the technical interview owing to its level of difficulty.

What are the 5 hardest interview questions? ›

The most difficult interview questions (and answers)
  • What is your greatest weakness?
  • Why should we hire you?
  • What's something that you didn't like about your last job?
  • Why do you want this job?
  • How do you deal with conflict with a co-worker?
  • Here's an answer for you.

What are the 20 most common interview questions and answers? ›

20 Most Common Interview Questions & How to Answer Them
  • Tell me about yourself.
  • What are your weaknesses?
  • Why should we choose you for this job?
  • What are your hobbies outside of work?
  • Where do you see yourself in five years' time?
  • Why are you leaving your current position?
  • What are your main strengths?
Jan 17, 2018

What are some tricky interview questions? ›

15 tricky job interview questions — and how to nail them
  • Can you tell me a little about yourself?
  • How did you hear about the position?
  • What do you know about the company?
  • What are your greatest professional strengths?
  • What do you consider to be your weaknesses?
  • What is your greatest professional achievement?

What is the STAR method in interviews? ›

The STAR method is a structured manner of responding to a behavioral-based interview question by discussing the specific situation, task, action, and result of the situation you are describing.

What is the 80 20 rule in interviewing? ›

As a rule of thumb, it is recommended that you spend just 20% of your preparation time researching the company in question, and 80% of your time focusing on yourself and your relevant skills and experience.

What are the top 3 interview mistakes? ›

Top 5 job interview mistakes
  • Being unprepared.
  • Dressing inappropriately.
  • Talking too much or not enough.
  • Criticising previous employers or colleagues.
  • Failing to ask questions.

What is the golden rule in interview? ›

3 golden interview rules: be prepared, be professional, and most importantly, be yourself.

Is C# a dying language? ›

Is C# dying? No. Microsoft has invested substantially in ensuring that C# is the dominant language today, spending two billion dollars on marketing and attempting to convince developers to embrace this new platform, which is also based on the.NET foundation. The .

Is C# more difficult than Python? ›

If you're wondering if C# is easier than Python, the answer is yes: the learning experience of Python is easier, though we have to admit that it's really not bad for C# either. Python also has lots of libraries that make coding a lot easier because you're not doing it from scratch.

What is the disadvantage of C#? ›

Disadvantages of C#Some of the disadvantages of C# are:The code in C# needs to be compiled every time a change is made. This can lead to many errors or bugs if the code is not tested thoroughly each time. A . NET application needs a Windows platform to execute and this is also true for C# as it is a part of the .

What are 5 tips for successful interviews? ›

Tips for a Successful Interview
  • Be on time. ...
  • Know the interviewer's name, its spelling, and pronunciation. ...
  • Have some questions of your own prepared in advance. ...
  • Bring several copies of your resume. ...
  • Have a reliable pen and a small note pad with you. ...
  • Greet the interviewer with a handshake and a smile.

What are the 5 steps to the perfect interview? ›

Five steps for successful interview preparation
  • Know your own brand. It's important to understand how others might perceive your brand in the market. ...
  • Be aware of your competition. ...
  • Be clear. ...
  • Listen and understand. ...
  • Give feedback.

What are 6 mistakes that can be made during an interview? ›

Avoid These Six Common Interview Mistakes
  • Bragging.
  • Answering but not asking.
  • Not knowing the company.
  • Not paying attention.
  • Making a bad first impression.
  • Trying to fake it.

What are three topics you should avoid in all interviews? ›

Topics to avoid during job interviews
  • Bad relationships with past employers. ...
  • Personal information. ...
  • Salary and benefits. ...
  • Past failures. ...
  • Gaps in your résumé. ...
  • Your side job. ...
  • Nervous chatter. ...
  • Your dearth of experience.
Jan 27, 2020

How do you know if a technical interview went bad? ›

13 signs an interview went badly
  • No introduction to other employees. ...
  • Lack of details regarding the role. ...
  • Focus on the negative aspects of the position. ...
  • Disengaged body language. ...
  • Lack of connection with the interviewer. ...
  • Rushing through the interview. ...
  • No discussion regarding the next steps.
Jan 1, 2023

Which is the toughest interview to crack? ›

Since SSB is a very tough interview and they want the right fit and not the best one, hence the reason for the vacant seats. The three-pronged selection style: In SSB three people access you from three different perspectives.

How can I impress a technical interview? ›

5 Steps to impress the HR in a technical job interview
  1. Be early. Coming early to an interview shows how dedicated you are. ...
  2. Be accurate. One thing that can cost you the job position can be inconsistencies. ...
  3. Don't lie about negative work experiences. ...
  4. Ask questions about the company. ...
  5. Follow up with a thank you letter.
Dec 8, 2020

What are the 10 hardest interview questions? ›

Top 10 Most Difficult Interview Questions
  • 'What do people most criticise about you? ...
  • 'Why do you want to change jobs? ...
  • 'What do you do when you know your boss is wrong? ...
  • 'Why should we hire you? ...
  • 'What do you like or dislike about your previous job? ...
  • 'Why was there a gap in your employment?

What is the biggest failure interview question? ›

They want to see whether you can learn from mistakes and how resilient you are . For this reason, it's not uncommon for you to be asked 'What has been your biggest failure to date and what did you learn from it? ' or variations on the theme, such as: 'Describe a time when something didn't work out as you had planned.

What are three key things that make a great interviewer? ›

The best interviewers have three qualities in common: they prepare well, have good communication skills, and are good at assessing candidates.

What are the 10 top tips for great interviews? ›

10 best interview tips to live by
  • Do your research. ...
  • Look sharp. ...
  • Don't show up empty handed. ...
  • Arrive early. ...
  • Project enthusiasm. ...
  • Listen carefully. ...
  • Give specific examples. ...
  • Ask questions.

How do you pass a 30 minute interview? ›

Here are some steps to help you rock your conference interviews.
  1. Write It Down. The best way to squeeze a lot of information into a short time span is to know ahead of time what you want to say. ...
  2. Broad Picture > Details. ...
  3. Distinguish Yourself. ...
  4. Prepare, Prepare, Prepare. ...
  5. Don't Know? ...
  6. 0 Comments.
Feb 7, 2023

What are the 23 most common interview questions and answers? ›

Correct Answers to 23 Common Interview Questions
  • Can you tell me a little about yourself? ...
  • Why are you interested in working here? ...
  • What do you know about the company? ...
  • Tell me about your previous experience. ...
  • What are your strengths? ...
  • What do you still need to work on? ...
  • How would your previous employer describe you?
Oct 1, 2019

How do you answer you don't have enough experience? ›

Using your own words, try something along the lines of: "I am interested in an entry-level position. I know I have much to learn, and I'm looking for an opportunity that will let me build a solid professional foundation. You say, 'Jump,' I'll ask, 'How high?

What are the 8 hardest interview questions and answers? ›

Common difficult interview questions with sample answers
  • What critical feedback do you most often receive? ...
  • Tell me about a time you overcame an obstacle. ...
  • How do you handle stress? ...
  • What have been your most positive and negative management experiences? ...
  • What's your biggest weakness?
5 days ago

What are the 5 star interview questions? ›

The most common questions are:
  • Tell me about a time when you were faced with a challenging situation. ...
  • Do you usually set goals at work? ...
  • Give me an example of a time you made a mistake at work.
  • Have you ever faced conflict with a coworker? ...
  • Tell me about a time when you handled the pressure well.
Feb 1, 2023

What color is best for interview? ›

Neutral colors - navy, gray, black, and brown - are the best colors for a job interview. White is also an excellent color for a blouse or button-down shirt. You can certainly add a pop of color to a neutral interview outfit.

What are the 4 steps in STAR? ›

Key Takeaways

STAR stands for situation, task, action, result. Each concept in the STAR acronym is a step that candidates can use to respond to interview questions.

How to Ace STAR interview questions? ›

As a reminder, the acronym stands for: S - Situation, T - Task, A - Action, R - Results. The format is quite straightforward to follow. Just make sure your answers are relevant, give proper context, describe your thought process, and finally, include real facts and figures.

What are main topics in C#? ›

Key Topics:
  • History and introduction.
  • Control statement, functions, arrays, and object classes.
  • Properties, inheritance, polymorphism, and abstraction.
  • Namespaces, strings exception handling, file IO.
Aug 15, 2019

What topics should I learn in C#? ›

  • C# Programming Language.
  • Introduction to .NET Framework.
  • C# | .NET Framework (Basic Architecture and Component Stack)
  • Hello World in C#
  • Common Language Runtime (CLR) in C#
Mar 5, 2023

What are the 7 parts of the C# program? ›

What are the main parts of a C# program?
  • Namespace declaration.
  • A class.
  • Class methods.
  • Class attributes.
  • A Main method.
  • Statements and Expressions.
  • Comments.
Jun 20, 2020

What are the important topics for coding interview? ›

Coding Interview Questions On Conceptual Understanding
  • What is a Data Structure? A data structure is a storage format that defines the way data is stored, organized, and manipulated. ...
  • What is an Array? ...
  • What is a Linked List? ...
  • What is LIFO? ...
  • What is a Stack? ...
  • What is FIFO? ...
  • What is a Queue? ...
  • What are Binary Trees?

Can C# have two main methods? ›

You can have more than one main method, you can specify which to use as the entry point for the application by your compiler. See this link for more detail. When I have 3 Main functions in different class files, only 2 Main methods available in "Startup object" option in Application property in the project.

What are the two types in C#? ›

The types of the C# language are divided into two main categories: reference types and value types. Both value types and reference types may be generic types, which take one or more type parameters.

Can C# run without main method? ›

Starting in C# 9, you don't have to explicitly include a Main method in a console application project. Instead, you can use the top-level statements feature to minimize the code you have to write. In this case, the compiler generates a class and Main method entry point for the application.

Can I learn C# in a week? ›

“If you have experience would take you a week to learn C#. One week, really,” Činčura says. “It's not a difficult language. You don't have to know all the bells and whistles.

What is unique about C#? ›

C# has features like Properties and Indexers. These features are not available in the Java language. C# supports Structures, Operator Overloading and Pre-processors directives, whereas, Java has none of them. Through C# we can easily call Windows API function and access COM components which is quite difficult in Java.

What is polymorphism in C#? ›

Polymorphism means "many forms", and it occurs when we have many classes that are related to each other by inheritance. Like we specified in the previous chapter; Inheritance lets us inherit fields and methods from another class. Polymorphism uses those methods to perform different tasks.

What are the 4 data types in C#? ›

C# mainly categorized data types in two types: Value types and Reference types. Value types include simple types (such as int, float, bool, and char), enum types, struct types, and Nullable value types. Reference types include class types, interface types, delegate types, and array types.

How many variables are there in C#? ›

C# defines seven categories of variables: static variables, instance variables, array elements, value parameters, reference parameters, output parameters, and local variables. The subclauses that follow describe each of these categories.

How many types of assembly are there in C#? ›

There are two types: process assemblies (EXE) and library assemblies (DLL).

What are 3 skills a coder might need to have? ›

Here are six important skills used in computer coding:
  • Language acquisition.
  • Innovative thinking.
  • Analytical skills.
  • Attention to detail.
  • Patience.
  • Communication.
Dec 20, 2022

What are the top five skills you need to be successful in coding? ›

5 Skills to Help You Thrive in Computer Programming
  • Problem-Solving. ...
  • A Sharp Memory. ...
  • Efficient Laziness. ...
  • Self-Motivation and Independence. ...
  • Perseverance.


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