OOPS Interview Questions and Answers | Object Oriented Programming Interview Questions C#

150 C# Interview Questions & Answers videos - www.questpond.com/c-interview...
This 1 hour of video covers most asked Interview questions with answers around OOP Concepts -
00:00 Introduction
02:58 Question 01 :- Why do we need OOP?
06:47 Question 02 :- What are the important pillars in OOP?
09:55 Question 03 :- What is a Class and Object ?
11:01 Question 04 :- Abstraction VS Encapsulation ?
16:28 Question 05 :- Explain Inheritance ?
18:15 Question 06 :- Explain Virtual Keyword ?
18:15 Question 07 :- What is Overriding ?
19:30 Question 08 :- Explain Overloading ?
20:50 Question 09 :- Overloading VS Overriding ?
23:04 Question 10 :- What is Polymorphism ?
23:53 Question 11 :- Can Polymorphism work without Inheritance ?
24:43 Question 12 :- Explain Static VS Dynamic Polymorphism ?
26:32 Question 13 :- Explain Operator Overloading ?
27:18 Question 14 :- How to do Custom Operator Overloading ?
30:16 Question 15 :- Why do we need Abstract Classes ?
34:10 Question 16 :- Are Abstract methods Virtual ?
35:27 Question 17 :- Can we create an instance of Abstract Classes ?
35:27 Question 18 :- Is it compulsory to implement Abstract Methods ?
36:44 Question 19 :- Why simple base class cannot replace Abstract Classes?
38:51 Question 20 :- Explain Interface and Why do we need it ?
40:11 Question 21 :- Can we write logic in Interface ?
40:11 Question 22 :- Can we define methods as private in Interface ?
46:58 Question 23 :- To change Interface what's the best practice ?
47:07 Question 24 :- Explain Multiple Inheritance in Interfaces ?
51:08 Question 25 :- Explain Interface Segregation Principle ?
53:09 Question 26 :- Can we create instance of Interface ?
53:33 Question 27 :- Can we do multiple inheritance of Interface ?
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[@digital.voyager]

C# 8.0 supports interface implementation methods, including default interface implementations, which allow you to add new members to a public interface without breaking existing implementers. I am little bit confused that why this change was made. @questpondvideos Could you please explain?

[@jaym4358]

Wow. I did not even notice the 1 hour pass by. This is the best interview prep and the best video that explains OOP concepts by far! Thank you so much.

[@jaym4358]

I had 3 technical interviews today. One of them had very heavy questions on OOP concepts. The interviewer loved my answer about what an interface is, and even admitted that he had a hard time grasping the concept earlier in his career. I passed that interview thanks to this video. I am moving on to the third and final round.

[@Father_Of_Sudeera_Muthusinghe]

@@jaym4358 Congratulations!!!

[@pranav288]

@@jaym4358 How was the final round ?

[@anshulasri152]

Answer to a question asked at last "Difference between abstract class with all abstract methods and and Interface" is that although both are technically similar but at the time of multiple inheritence abstract class fails, for multiple inheritance we have to implement Interface only. Also I would like to thank you for the video that explains concepts so easily with code examples!

[@theav.1313]

Thank you! I’m so glad you’re showing real time coding examples while explaining each necessary details. I’m learning a lot from this video. I can’t wait to watch your other videos! Thank you!!!

[@dominiquez5643]

Master class! Wow 20+ years developing and at last somebody explain things in a simple concrete manner! This is an amazing run down on OOP techniques properly exlained to be used and to answer questions from anybody in IT! Love this video!

[@nikhilkohirlyakaji]

This video has cleared my biggest confusion related to Encapsulation vs abstraction which I have been facing for over 5 years now. Thanks

[@vinothrajendran858]

Sir, I have suggested your videos to nearly 20 people(my friends and colleagues) who were all trying for their next job and they found your videos really helpful. we are forever grateful. Thank you so much :) . And I will keep spreading your channel videos.

[@danyahsan3958]

did you get the job

[@sridhargana155]

An abstract class allows you to create functionality that subclasses can implement or override. An interface only allows you to define functionality, not implement it. And whereas a class can extend only one abstract class, it can take advantage of multiple interfaces.

[@phelipepalte]

Another difference between abstract class and interface is you can't do a dependency injection with abstract class..

[@X3sView]

Latest version of c# allow interfaces to provide default implementation

[@bosegeorge1425]

​@@phelipepalte actually you can.

[@stepbackandthink]

You have explained this far better than actual training videos.

[@automationselenium1331]

By far the best video on C# interview I have seen on youtube, how one hour passed I have no idea, your way of teaching is amazing and I can watch your videos for hours...thank you and god bless you.

[@sunrise7442]

Best video's ive ever came across that explains concepts so easy. I followed the questions and enrolled on Udemy for the extra questions not covered here, and Cleared my first interview after 15min post interviewing I was called by HR that I got the Job🎉🎉 kudos to you Sir.

[@Father_Of_Sudeera_Muthusinghe]

One thing to notice... When we are talking about method "overriding vs overloading", we should emphasize that method overriding is a runtime polymorphism and method overloading is a compile-time polymorphism. I guess it will be an expected answer in an interview. Finally, thanks for this interview question video. It helps me a lot to gain self-confidence before going to interviews.

[@KathakathanKarya]

Yes. Also we should talk about method signatures.

[@priyeshdubey40]

but here is the catch he also told that without inheritance polymorphism will not work but you see overloading case which is example of compile time polymorphism is not following the inheritance thing ..I think he confused little bit.😉

[@Father_Of_Sudeera_Muthusinghe]

@@priyeshdubey40 yup. U r right. In the comment section he has accepted the mistake. Anyway a great video.

[@gazalkaintura2605]

@@priyeshdubey40 exactly I thought the same thing

[@hemantvitthal3732]

Aftter many year (10 years) search on google or youtube, I found best programming concept, What I exactly needed. Thank you @Questpond.

[@dequanjabooty7379]

IMO, your c# (and other) videos are some of the best on KZbin. They are very helpful. I plan on ordering your courses on your website. Thank You

[@raoadnan442]

Awesome way of describing. I have been searching OOP interview question answers but unable to find a great teacher like you. Hurrah.. now I have. Love from Pakistan. Keep doing this great job.

[@fernandod3510]

You have a real talent for education and clear explanation. Thank you for all you have given.

[@seijumimurasakibara5516]

your dry wit coupled with your easy to understand explanations makes this video enjoyable to watch! thank you for this, i've finally understood the difference between abstraction and encapsulation and learned couple more things as well. Please keep up the good work!

[@questpondvideos]

Thank You :)

[@natnaelhabtamu2799]

THIS is GOLD, you can easily follow up with any OOP language. thanks sir 🤗

[@panic_seller]

Very good video, never paid attention for 1 hour in a KZbin video

[@vedantkulkarni5437]

One suggestion to viewers....don't skip this video just because you are using different language other than cs....it is one of the best video for oop with proper explanation

[@dorothyfung5605]

Thanks very much for preparing and explaining stuff in such clear and organised way! :)

[@lehcyllehc]

Thank you for this. I know you put so much effort and I gladly appreciate it. The way you explain each questions are easy to understand. I subscribed and liked this video. Looking forward to all your videos. :)

[@omarcollazo5011]

This is the best explanation of abstraction vs encapsulation that I've ever heard. Thank you, sir!

[@binayashrestha4131]

Best OOP explanation video in KZbin !

[@vaibhavraj581]

Very intuitive and clear explanation of the concepts , thanks a lot for sharing. Looking forward to learn more from your videos.

[@izmar47]

Thank you for the lesson. I can't tell you how much this helped. I appreciate your effort. Liked and Subscribed!

[@hakeemshodimu1956]

Great prep, very concise and to the heart of the matter

[@hirajabeen9681]

I am here to recall my concepts and I have seen lots of material pdfs , YT vids and consult with books as well but this video I must say is so accurate and totally concise and delivers exactly what anyone need ! Much Appreciation for you ! Hatts off to your Efforts ! More Power To You ! @Questpond

[@questpondvideos]

Thank You 🙏

[@mariahaamir171]

Its really underrated channel; I my opinion its by far the best. I am following Questpond since 7 years

[@lavanyaguniganti1444]

Sir, I have cleared my interview in reputed MNC just by going through your interview videos. thank you so much

[@rangababupolavarapu517]

Do you have more interview questions

[@questpondvideos]

@@rangababupolavarapu517 you can visit www.questpond.com/interview-questions---answers-tutorial/cid63 for interview Q&A videos

[@chanauria]

I love your video! Very well explained! Keep it up!

[@gametechtutorial4670]

Best video so far. Clear, right at the point. Im getting the point right away. Thank you for sharing the knowledge sir.😃🙇‍♂

[@benedictmabanga5736]

Best explanations! Thank you for this🙏🙌

[@SSSALLJOBSPORTAL]

Wah!! What an explanation boss!! Crystal clear explanation... 🙌 really thank you🔥

[@naseerhussain5272]

This is the Best Explanation one could have asked for

[@judycariaga3945]

You really great at explaining it. Now I understand the OOP more. Thank you so much. ♥️

[@rajeshmacpant]

Excellent. This is such an easy refresher or explanation of OOPS concepts.

[@PabloMartinezfr]

Best OOPS Interview Questions and Answers on KZbin!

[@vidyamahathi6057]

I got a job.I just watched this video for oops concepts 😁

[@husnainmazhar6739]

amazing video,, cleared all the concepts.. Thanks

[@jankichalise904]

I always knew the theory part but when it comes to interview every interviewer was like what's the practical implementation of it and i really found the answer nowhere. thankyou so much for taking efforts and making an awesome video

[@ShankarV-te7le]

Simply superb explanation...thank you @Questpond.

[@Devdumplings]

This is the best one compared any oops languages. Having come from a different language background finally I understood what exactly the concepts clearly and thanks for being realistic about the preparation importance as I was a unprepared hero 😂

[@kelpiekrisps]

This was real great, thank you!

[@shivamsoni4215]

Thank you for making simple topic complicated ♥

[@godwinchalz4863]

best video for oops in C#

[@unknownfacts1197]

Multiple inheritance is what makes interface and abstract class differ from each other when they become technically similar

[@questpondvideos]

So right. Thats the only BIG technical difference

[@unknownfacts1197]

@@questpondvideos Thank you.. Your explanations are so good sir 👍

[@jurijdevelopment1241]

Brilliant explanation! Keep doing more videos!

[@deepz513]

thank you sir, along with deeply explaining the concepts you are valuable advised is much appriciated.

[@shivangisingh9920]

You are awesome... Helped me a lot in the interview.

[@muhammadalikhanshirwany9378]

answer to the last question if later on they wat to add a new functionality or new method , in abstract class we cant use multiple inheritance but in interface we can .. i hope this is the answer.. thanks for your videos it helps allot. great work👍

[@abdullahahmed8468]

amazing content with clear and simple answers, Thanks alot

[@mahinatarajan4232]

Hi Sir, Regarding Interface, should we follow the rules implied from C# 8 features? Because in C#8, we could provide access modifiers explicitly and it can contain default body implementation which can be accessed by up casting it.

[@gopavarapuguruprasad]

One of best video about oops concepts interview question and answers I come across. Please keep up good work sir👍.

[@phanirao2008]

wonderful, very crispy, specially example taken easy than domian specific

[@lekhrajawasthi8272]

Thank you shiv sir for this easiest explanation. Answer to that last question is that : Abstract can't help in multiple inheritance but the Interface can do the multiple inheritance. So in case of any modification to the requirement one can easily modify interface by implementing multiple inheritance.

[@EdisonSeas]

Great video, for understanding OOP concepts not just for C# but also any other language even if they don't support them, (like JavaScript). Pura vida!

[@saravanansangeetha1206]

Very very useful video for us, appreciate your efforts

[@reddit_thoughts_now]

Thanks for the video, it was very helpful!

[@mohamedmusthafa1057]

I find this Channel You saved My lot of time thanks ❤

[@yilienchi5380]

I like APIE concept! That's pretty helpful! Thank you so mcuh

[@nithunandhugaming6519]

No one cant explain this much easier in overriding and virtual keyword concepts

[@nalinikantadash8669]

An Interface contains methods which are by default abstract.But as an abstract class is a partially defined parent class so there is a possibility that it can contain both abstract methods as well as non abstract methods.This is the basic difference between an interface and an abstract class.

[@kishanpatel6657]

Very good point to point.

[@manpreet.mg16]

You have done great video short and ans to remember in easiest way

[@justiceeziefule9308]

This is well explained. Thank you bro

[@praveenrajubattula701]

Good video. Just 1 correction - interface can contain implementation, which was implemented in c#8.

[@yogeshbrahmane4200]

You are Best Sir !! Really very helpful

[@akshaysoren5400]

Thank you so much sir. i really like the way you explain.

[@Aalii6]

very helpful, thank you! 👍👍

[@amamsharma372]

Thanks you for uploading

[@AzeemRaavi]

Awesome way to answers the OOP questions. Love from Pakistan 🇵🇰

[@kingfisher3791]

What most anyone can say about this video, it is really awesome. After seeing this i come to know what the purpose of oops concepts

[@the_ssr__]

THANK YOU FOR THIS VIDEO

[@keerthanasaiprasad6631]

Love this video! Could you make one for Java Core Interview questions?

[@mahydulislam]

thankyou so much for your nice explanation

[@akashgupta2971]

Huge respect for the efforts and time that you and your team have put, the sequence of the questions were very connecting and gradual... Now I have a better concept after watching the video... And for the question you asked at the end of the video... My answer is that abstract classes can be partially or not implemented whereas interfaces should be fully implemented.

[@yosiosibemekun2785]

An interface only allows you to define functionality, not implement it.

[@akashgupta2971]

@@yosiosibemekun2785 yeah that's another difference

[@manjuanoop7239]

Excellent material thanks for sharing such an informative video👍🏻

[@nks98968]

Very knowledgeable..Thanks

[@shubhampanwar7647]

very very detailed and good quality video. i watched till question 27

[@Shubhamkumar-ir5ox]

Thanks Sir. Much more Appreciated.

[@sadakagaja]

Awesome sir It helping me to learn C#❤️

[@AhmedAdel-xg1cm]

Very intuitive and clear explanation of the concepts , thanks a lot for sharing. hope u will make a video for solid principles

[@priyeshdubey40]

You told that without inheritance polymorphism will not work but you need to see overloading case which is example of compile time polymorphism which is not following the inheritance thing ..

[@surya-tl3uy]

Amazing content!!...Thank you :)

[@CALLMEMANISH82]

thanks, very beneficial video to revise oop concepts.

[@legendgattu]

Abstraction is exposing only whatever is necessary outside a class. Encapsulation is binding data and behaviour (methods) together.

[@vagatsinghrathore1756]

Really awesome, thank u so much 🎉

[@rabinsrai5078]

Great work sir,thanks

[@nagaboddu852]

Thank you sir , it’s very useful 😊

[@hdching]

Thx a lot!!! Well-prepared video

[@mohanaPriya-wr1lf]

Great teaching 👌👏

[@abdulrehman8957]

Thanks for this video, you explain very well about OOP concepts and your presentation skills are too good. Well done and keep it up.

[@durgaprasadgarapati1748]

Waiting for this video sir thanks for sharing

[@sarithakotha4138]

Thank u so much… This is so helpful for me

[@elotfreelancing1791]

i have never seen, a video so to the point.

[@user-ek5jw3cl7k]

24:38 Inheritance is not must for polymorphism as you can implement static polymorphism without inheritance. Please let me know sir if you had a different mean.

[@ankursahani8564]

Sir your explanation is very systematic. Sir please upload Question and answer for top 50 C programming coding Question for fresher interview.

[@triloksingh1579]

Hello Shiv Sir You are great

[@kishanpatel6657]

Thank you again 😇🙏🏻