How to Pass an Interview for a Software Engineer?

1. How to Pass an Interview for a Software Engineer? What to Do and What to Avoid? Svetlin Nakov Ph.D., Computer Science www.nakov.com Sofia, 3.05.2011

2. Contents • What is a Job Interview? • Preparation for an Interview • Typical Interview Questions and Answers for Software Engineers • Classical Questions • Technical Questions • Non-Technical (Personality) Questions • Questions to Ask • Typical Mistakes and How to Avoid Them?

3. What is a Job Interview? A Stressful Situation or a Chance to Demonstrate Your Knowledge and Skills?

4. What is a Job Interview? • A job interview is a meeting aimed to assess a candidate for a certain job position • The candidate should prove he or she is the right person for the offered position • The interviewers asses the skills of the candidate and his or her personality • By questions and small tasks • The candidate tries to prove his or her skills • The candidate demonstrates his or her personal character

5. How to Overcome the Stress? • The job interview is a stressful situation! • You need to present yourself in the best way • In most cases candidates fail to demonstrate their skills due to stress • How to overcome the stress? • Just be well prepared! • Prepare yourself for the technical and non-technical questions • Expect the questions and have good answers

6. Interview Preparation What is the Best Way to Prepare Yourself for an Upcoming Interview?

7. Steps to Prepare for an Interview • Once you have scheduled and interview, be sure to prepare yourself for it • It is important to put enough effort in your interview preparation • Half an hour is not enough, invest at least few days • Steps to prepare for an interview • Research the company • Research the offered position • Prepare for technical questions

8. Research the Company • Always research the company you apply for • You should expect a question at the interview like "What do you know about our company?" • If you answer "Nothing", you will fail • If you say something incorrect, it is even worse • How to find information? • Obligatory explore in details the company Web site, brochures, publications, ads, etc. • Look for articles, blogs, forums, etc. • Ask your friends what do they know

9. Research the Company (2) • What information you should know? • The company products / services portfolio • The target market and customers • The technologies used in the development (e.g. C#, Silverlight, SQL Server, RIA Services, etc.) • Download the products and play with them • You will be asked what you know about the products related to your prospective job • The company mission, vision, projects, etc. • The corporate culture, corporate values

10. Research the Offered Position • Obligatory research the offered position, requirements, advantages and responsibilities • You should research all mentioned products, services and technologies in the job description • E.g. if you see "Experience with Selenium is a plus", be sure to install and play with Selenium • Be sure to know all "unknown words and acronyms" in the job description • Be ready to demonstrate skills and experience in the fields from the job description

11. Prepare for Technical Questions • How to prepare for the technical questions? • Typical general technical questions • Data structures and algorithms • Logical thinking and puzzles • Software engineering questions • Object-oriented programming (OOP) • Specific questions for the offered position • If the job description says "JSF and RichFaces", you should learn these technologies

12. Prepare for Technical Questions • How do you prepare for a certain technology? • Pass a course / tutorial / read a book / blog article about the unknown technology • Obligatory create a small project using the technology and play with it • This is the only way to get some real-life experience, live in a project • If you have never used a certain technology (e.g. JSF) you cannot say you are prepared • The best way to learn it is by practicing

13. The Interview Process Typical Scenario for a Technical Interview

14. Technical Interview: The Process • A technical interview for software engineer consists of the following parts: • The candidate presents himself or herself • The interviewers present the company, its business, products, services, etc. • Technical assessment – solve few technical problems and demonstrate the way of thinking • Personal character assessment • Negotiation – salary expectations, start date, …

15. Presenting the Company / Position • Typical start of an interview: • The interviewers presents themselves • Usually there is more than one interviewer • The interviewer presents in short the company, his department, his team, the current and upcoming projects, technologies used, etc. • Some companies skip this step and expect the candidate to know all this stuff My name is … Our company is … bala-bla-bla … We are leader in … bla-bla-bla … Our products bla-bla-bla … Our projects … bla-bla-bla … We are the best!

16. Presenting Yourself • Typical next step in an interview: • The candidate is expected to say few words about himself / herself • Be prepared to talk 3-5 minutes • Explain how did you start programming • Your last job and projects (if you have) • Your current occupation (e.g. student in NBU) • How did you learn about the position and your motivation to apply Present yourself in short – your relevant experience, education, how did you start programming, etc.

17. Technical Assessment • The technical assessment is the most important part of the interview • You will be given technical questions to answer and technical tasks to solve • Always come with a pen and writing pad • It is not so important whether you solve correctly the tasks or answer correctly • You should demonstrate your way of thinking! • The interviewer wants to know how you attack the problem, not whether the result is correct

18. Technical Question – Example In C# which explain the fastest algorithm to sort a list of customers by their first name? • You should demonstrate your way of thinking by saying what you think at the moment, e.g. • Being silent for a minute while you think is evil! … I know the build-in Array.Sort() method, but I am not sure it is the fastest. If I had a computer I would perform a Google search. For multi-core CPUs I could try the parallel sorting using LINQ with parallel extensions. I should either implement own comparer or use a lambda function to sort by the FirstName property.

19. Technical Task – Example • Suppose you are given a simple problem like: • The first thing to do it to get the writing pad and write an example! • This shows a correct and serious way of thinking • By using the pen explain how you could randomize the sequence of cards • Explain how you will represent a single card and a sequence of cards (data structures) • Explain how you could test your solution How do you can randomize a sequence of playing cards?

20. Personal Character Assessment • Assessment of your personal character qualities is very important for the company • Good software companies will weight your personal skills more than your technical skills • You will be asked somehow irrelevant questions that reveal your character, e.g. Do you have experience working in a team? What do you prefer – being a leader or a player? Do you play some kind of sport? At what position? How do you react if you are about to miss a deadline?

21. Personal Character Assessment (2) • At the personal assessment questions there is no correct or wrong answer • Just be you • Don't recite some other's words • Very important: be positive! • Negative people are not welcome anywhere • Be confident • Don't say "I don't know" • Demonstrate willingness and ability to work in a harmony and with pleasure with the others

22. Negotiation • If your interview runs well, you will reach the "negotiation" part • Salary expectations – always have a good answer • Eventual start date • Other terms of the contract (bonuses, holidays, working time, etc.) • Companies don't like "money-driven" employees • You should demonstrate motivation to work hard for long-term and continuously improve your skills

23. Your Questions • Finally you will have a chance to ask your questions • Having no questions is not good • Demonstrate interest to start working • Ask about your first project, about the development process, about your team, etc. • Never ask about salary raises, bonuses, parking space, fitness and sport facilities, etc. • You should demonstrate motivation to work hard, not claims

24. Typical Interview Questions and Answers (for Junior Software Development Positions)

25. Typical Interview Questions • At a technical interview you will be given questions from several categories: • General questions • Technical questions • Abstract thinking questions • Personal character questions • The "salary" question

26. General Questions Experience, Education, Future Plans

27. Typical General Questions Where are you from? What High school have you graduated? What University have you graduated or you are studying now? When you started programming? How many books about computer programming you have read? What was the name of the last? Do you believe that computer programming is your passion and your future job? Can you work on full time (8 hours/day)? If not how many hours a week you can work?

28. Typical General Questions (2) What are your English skills? Can you freely talk on the telephone in English? What are your plans for the next few years? How you see your career after 2 or 3 years? How you inform yourself about new technologies? Do you read news or blogs? Which sites? Shall you study more after you graduate your current University degree? Maybe abroad? Describe your typical work day.

29. Technical Questions Algorithms, Databases, Web Technologies, Etc.

30. Typical Technical Questions • Algorithms and data structures: Can you draw a picture of a linked list? What is typical for the Strings in C# / Java / PHP? Explain how polymoprhism works in the object-oriented programming (OOP)? Explain what is a hash-table and how it works. Explain how the QuickSort works. How fast is it? You are given a set of words. Find all their subsets. You have to implement a Web spider which runs on a cluster of machines. How you will design it?

31. Typical Technical Questions (2) • Databases and SQL: How we implement one-to-many and many-to-many relationship in relational databases? When we use "1 x 1" relationships in database modelling? Give an example. What is database constraint? How constraints work? You have a table consisting of: EmployeeId (PK), Name, Salary, ManagerId (FK), DeptId (FK). Write a SQL query to find the name, salary and department of the employee that has minimal salary in his/her department. If many employees take the minimal salary, display just one of them.

32. Typical Technical Questions (3) • XML questions: • Multithreading questions: What is the difference between DOM, SAX and StAX parsers for XML? How you use DOM in C# / Java / PHP? What is XPath and how it works? Give an example. How you use Xpath in C# / Java / PHP? How we execute multiple tasks in the same time in C#? You have to download 500 files from Internet but your network bandwidth is not too wide to handle 500 downloads simultaneously so you want to download the files by 10 at a time. How you implement this?

33. Typical Technical Questions (4) • Web development questions (front-end): Explain the difference between HTTP GET and POST requests. Explain the meaning of the following CSS rule: .newscolumn { width: 400px; float: left; clear: both; } We have a <div> element in a HTML page which is visible. How to hide the <div> with JavaScript? How to do the above in jQuery?

34. Typical Technical Questions (5) • Web development questions (server side): How you could implement a shopping cart in ASP.NET / Java / PHP? What is custom tag / user control in a ASP.NET / Java based Web application? How it works? When we need this technology? What is AJAX and how it works? How we use AJAX in ASP.NET / jQuery / PHP / Java based Web application? We have a list of products that have name, price and photo. We need to display them in a Web application. Describe the steps to do this in ASP.NET / Java / PHP. How we implement URL rewriting in ASP.NET / Java Web application / PHP?

35. Typical Technical Questions (6) • Software engineering questions: What is software requirements specification (SRS)? What is the typical structure of such document? What is source control repository? Which source control software you have used and when? What is unit testing? When we need it? What unit testting frameworks you have used? How the continous integration works? Explain what is agile development. What is SCRUM? Explain the most important practices of SCRUM.

36. Abstract Thinking Questions Puzzles, Unsolvable Problems, Etc.

37. Abstract Thinking Questions • Questions in the category "abstract thinking" aim to check the level of alertness, ability to think and to attack unsolvable problems • In some cases there is no correct answer and your task is to demonstrate your thinking Estimate how many gas stations exist in Sofia. Do you see the tree outside on the street? Can you calculate how many leaves it has? You have 8 balls. One of them is defective and weighs less than others. You have a balance to measure balls against each other. In 2 weighings how do you find the defective one?

38. Personal Character Questions Your Best and Worst Qualities, Ability to Work in a Team, How do you Handle a Stressful Situation?

39. Typical Personal CharacterAssessment Questions • Questions to assess your personal character: Describe the ideal software company from your dreams. Can you describe an ideal collague / team member? What are your 5 best personal character qualities? What are your 5 worst personal character qualities? What kind of sport do you practice? At which position do you play? What shall you do if you have a deadline until tomorrow and your project is not completed? How do you resolve a conflict with a colleague?

40. Typical Personal CharacterAssessment Questions (2) • Questions to assess your personal character: Do you prefer to work independently or in a team? Give some examples of a team work from your experience. How do you resolve a conflict with a colleague? What does motivate you and what does not? How do you handle stress and pressure? Describe a difficult work situation / project you have experienced and how you overcame it. How you can evaluate your results. What is success?

41. Typical Personal CharacterAssessment Questions (3) • Questions to assess your personal character: What were your responsibilities at your last job / last project? What major challenges and problems did you face? How did you handle them? Why are you leaving your current job? What interests you about this job? What challenges are you looking for in this position? Why we need to hire you, not someone else?

42. The "Salary" Question How to Answer in the Best Way?

43. The "Salary" Question • The typical salary question is like this? • Your answer should demonstrate that your work is more important than the payment • Examples of possible answers: What salary do you expect? I don't care about the payment. I want to work at the company for long-term and I believe that if my results are good I will be paid accordingly. I understand that I have to learn a lot. Thus now I think I could start with a salary of XXX leva and in a year I expect to become more skillful and get a pay rise of YYY (or be fired if I don't meet your expectations).

44. The "Salary" Question (2) • You always talk about a net salary (after all the taxes are deducted) for a full-time job (8 hours) • Some candidates will say: • Some companies have a policy for this case: • Most companies will force you to say a certain number and you should say something – be ready! I don't know what salary to expect. Please make an offer for me. You will be a junior developer (trainee). For this position our salary range is from XXX to YYY leva.

45. The "Salary" Question (3) • Typical net salary ranges (Sofia, May 2011) for full-time software engineer jobs: • Junior .NET / Java developer – 600-900 leva • Junior PHP / Web site developer – 400-700 leva • Junior QA engineer – 500-800 leva • Junior support officer – 400-700 leva • Junior system administrator – 500-800 leva • After a 1-1.5 years you could expect twice • Senior developer (4-5 years) – 2000-3000leva

46. Typical Mistakes and How to Avoid Them? One Wrong Word Could Spoil the Deal!

47. Typical Mistakes • Never say bad words about former employers, colleagues, etc. (don’t hate anyone) • Always be positive! • Typical "catch-you" question • Possible nice answer: Did you have colleagues or classmates who you can't stand? What were they? Why you can't stand them? Generally I can stand anyone. I don't like too much XXX kind of people but if I need to work in a team with such colleagues I will defenitely find a way.

48. Typical Mistakes • Generally all kinds of inadequate claims or pretentions are evil • Requesting too high salary, too high position, too short work-time (less than 8 hours / day) • Being negative about something or someone • Be positive, be successful, be skillful, be professional, don't blame somebody else! • You should demonstrate high motivation to work hard for long-term • Anything confirming the opposite is harmful

49. Typical Mistakes (2) • Requesting too high salary • Requesting too high position for a start • You should always show willingness to work for a long-term This is my first job and I want to start with 1800 leva net salary because I am very smart and experienced. I want to start a job at some management position because I have graduated University in UK. I will work in your company for few months and will go abroad for a better job after I get some experience.

50. Typical Mistakes (3) • Putting university / exams as your first priority • You could say the same in a better way I want to start working but my University education is my first priority. Thus I will be unable to come at work each Tuesday and each Wednesday and when I have tests, exams and projects. My first priority is my job. In the same time I have some commitments in the University but I am flexible to do my best to move them out of working time. Sometimes (e.g. once monthly) I will have to take tests / exams in the University and I hope we could find a way to avoid harmful consequences for my projects at work due to my eventual absence. Do you think this would be possible?