Technical Interview Questions for Computer Science 2021

Any successful company has to get on top of the process of interviewing job candidates. This is time-consuming for any business, but a major company requires both an HR department and significant time and effort from its professional and executive staff.

But when it comes to hiring computer scientists—IT engineers, software developers, systems architects, program debuggers—the process takes on a whole new layer of complexity. Among the most important capabilities to assess are technical knowledge and skills. Basic computer skills, programming skills, writing code to define and solve problems, managing databases, and working with servers are all needed for technical roles in your company. So is communicating as a member of a development team.

The technical interview is inescapable, and every company that seeks computer-engineering talent, for whatever role, has its distinctive approach to technical interviewing. Selecting the right questions for a given engineering role, preparing for interviews, conducting them, evaluating the results—and perhaps going back for another round or two—consumes time and intellectual energy.

And how often does the technical interview get at the candidate’s potential performance in the job? There are plenty of lists of the top 50 computer science interview questions. But answering “Why did you choose computer engineering?” interview questions or “How do you describe your level of computer skills?” does not test technical skills—certainly not application of skills to solve problems that will be encountered on the job.

Posing the most common computer science technical interview questions does not guarantee objective evidence of how well a candidate will do in his or her role (for example, Front End Developer) or how well the candidate performs a core skill like coding in the context of a particular challenge.

In our guide to conducting the technical interview, we discuss how to interview someone and why the technical skills interview process is time-consuming, biased, tiring, and isn’t thorough. Worse still, you may end up with the wrong hire.

You observe as each candidate demonstrates how to solve algorithms and data structure challenges on the whiteboard…. However, [for the candidate], even after reviewing technical interview question examples, being asked to write code under a microscope can overwhelm the brightest of programmers.

Computer engineering interview questions

The full computer engineering interview (which might be in three or four parts, beginning with the HR department) will cover questions about degrees and certifications in technical fields, job history, career plans and aspirations, and, crucially, technical skills that will be required on the job and by the team.

Programming skills

These are questions about coding, programming languages, operating systems, computer hardware and software, and other aspects of computer systems that ask the candidate to explain some of the vast technical vocabulary of computer science. A drawback is that defining and explaining concepts is not the same as applying them to the problems the successful candidate would face on the first day of work.

It is likely that the individual hired for the role will spend a lot of time writing code, which needs to be clean and effective. A relevant question is what programming languages the candidate prefers. There is no right or wrong answer from the candidate’s perspective, but for many companies, Java (for example) is built into their entire software complex. Or, a company designing internet platforms might use mostly JavaScript.

Here are a dozen examples of common computer science questions interviewers ask:

  • How many types of access modifiers are there? Name and define each one.
  • Name the main types of constructors.
  • What is the transport layer?
  • What is the difference between an interface and an abstract class?
  • What is an abstract class?
  • What is an abstract keyword?
  • Provide some C source code.
  • Name a type of balanced binary tree. Explain how it is implemented.
  • How does the central processing unit (CPU) function within a computer system?
  • What is GitHub, and how do you use it?
  • What is an array?
  • What is an operating system? Give some examples of common operating systems in use today.

Candidates can also use this technical interview questions and answers pdf to practice for the technical interview. Computer science interview preparation should be relevant to the role the candidate would fill, the level at which the candidate is being hired, and the kind of work being done by the development team.


After assessing programming skills, the interviewer will ask questions to get to know the candidate and see how well they would suit the organization. In fact, behavioral questions loom large in the hiring process of most companies, from tech giants to new ventures.

Usually, the behavioral question asks the candidate to give an example:

  • Tell us about a time you had to ask for help on your work and how you did it.
  • Can you give me an example of a time you were assigned a role on a team and felt it was the wrong use of your strengths?

Other behavioral questions ask for self-assessments by the candidate:

  • What do you see as your chief strengths and weaknesses in computer science?
  • How have you handled working on multiple projects or problems?
  • Why should we hire you?

Technical communication

Software development and other teams have become so pivotal to tech innovation at most companies that a candidate’s ability to communicate technical ideas, problems, and proposed solutions is viewed as critically important. For example, a prime requirement for a Full Stack Engineer is constant communication between the Back End and Front End teams to ensure smooth integration.

Interview questions on computer skills

Any interview that evaluates a candidate’s computer skills has limitations, but those limitations are serious and unavoidable in the technical phone interview. At least the initial attempts to recruit and screen candidates often take place on the telephone. Most of the questions we have discussed can be asked over the phone, but the phone interview emphatically does not test computer skills.

Computer skills must be used by the candidate if interviewers are to evaluate them. The online coding challenges created by Woven and customized for our clients are assessed using our Scenario Evaluation Engine that tests code writing in the context of defining and solving problems the candidate would face on the job. Our platform is the only technical assessment tool to measure a candidate’s skills in areas like software development, debugging, systems architecture, and collaboration on a technical team.

Woven is the only human-structured approach to scoring to evaluate the whole candidate. At least two of our senior engineers separately assess the test and report their results and recommendations. Human scoring means that the test goes beyond a “right or wrong” answer sheet; candidates may have incorrect or less than ideal answers, but their setting-up of the problem, how they use code and other tools, and their suggested solutions all convey vital information about their technical skills.

Another benefit that company engineers and candidates themselves appreciate is the objective feedback on performance given to every candidate who tests with Woven. We’ve received tons of positive comments from candidates, like this one: “I give this feedback a 5 because not only does it entail what I should have done and what I did, it also includes ways to better myself.”

Technical interview questions computer science for freshers

CodingCompiler offers computer science interview questions and answers for freshers with examples of that “every computer science student must know,” including, of course, new graduates with computer science degrees:

  • What is the definition of a computer system?
  • What are the basic components of a computer system?
  • What is a Microprocessor?
  • Mention some of the latest Computer Processors.
  • What is the difference between 32-bit and 64-bit processors?
  • What is the best operating system? Mention some popular OSes.
  • What is primary memory and secondary memory?
  • What is a chipset?
  • What do you know about the OSI Model?
  • What do you know about the TCP / IP model?

What applies to testing the level of skill, also applies to testing capabilities to fill different roles in computer science. Woven online coding challenges are role-based to evaluate the whole candidate for essential engineering skills. These are the key roles in computer engineering on the teams that carry out a company’s innovative, quality control, emergency response, and other functions:

  • Mid/Senior Fullstack Engineer
  • Junior/Mid Fullstack Engineer
  • Engineering Manager
  • SRE/DevOps Engineer
  • Mid/Senior Frontend Engineer
  • Junior/Mid Frontend Engineer
  • Mid/Senior Backend Engineer
  • Junior/Mid Backend Engineer
  • Mid/Senior Generalist Engineer

Our online challenges use real-life scenarios to engage essential engineering skills: debugging, technical communications, systems thinking, back-end programming, and front-end programming. However, these mixes and levels of skills vary greatly from role to role. Defining each role can help you test the right candidates and forge the right instrument.

Coding interview questions

At Woven, two propositions always go together:

  1. Online coding challenges are indispensable to efficient, cost-effective, and fair/unbiased assessment of computer science technical skills.
  2. Companies need a technical assessment program that goes beyond code.

In your free trial of the Woven assessment platform, you will see how computer languages, coding skills, and tool-use are just part of a real-life problem-solving scenario.

The problems test the candidate’s engineering skills used in debugging, technical communications, systems thinking, and skills required by a role such as Front-End Development. Specific questions are selected for the candidate’s experience level and the job role sought.

Then, to borrow a computer development metaphor, the process moves from the Back-End—the creation of the test and its administration—to the Front-End—evaluating the test results for the client, making recommendations, and offering feedback for candidates.

How to ace a phone interview

Usually, it is the candidate who asks how to ace a phone interview.

But now, there is a powerful tool to help you, the interviewer, overcome the limitations of the telephone technical interview. That interview itself cannot test technical skills. You might obtain an impressive first grasp of a candidate’s technical vocabulary, ability to explain and relate technical concepts, and communicate problems and ideas as would be required on a team.

But if the initial screening decision is reached on that basis alone, a candidate who can write superb code, use it to set up a problem, and suggest solutions might be screened out, whereas a highly articulate and informed student with an academic grasp of computer science is accepted.

Woven’s technical assessment platform sets up the telephone or in-person interview to play a productive role in hiring. With that vital job requirements already screened objectively, interviews can tackle questions of behavior at work, suitability to your company’s culture, ability to communicate, and career direction and aspirations.

Plus, employment of our online challenges is scalable. It’s tough to fill a dozen computer science positions at the same time or to create a new software development team. You are looking at hours of recruiting, screening, and final interviewing. We can vastly reduce that time and effort while enabling more reliable hiring decisions because candidates have demonstrated what they will do on the job, in the role you need, from the very beginning.

You can learn more about our method, products, and way of working by starting your free trial today.