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

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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[jaym]

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.

[anshulasri]

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!

[nikhilkohirlyakaji]

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

[vinothrajendran]

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[dominiquez]

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!

[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.

[sunrise]

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.

[sridhargana]

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.

[lavanyaguniganti]

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[seijumimurasakibara]

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! <3

[theav.]

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!!!

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[vedantkulkarni]

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

[stepbackandthink]

You have explained this far better than actual training videos.

[hirajabeen]

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[unknownfacts]

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

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[omarcollazo]

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

[raoadnan]

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