Liskov's Substitution Principle | SOLID Design Principles (ep 1 part 1)

What is the Liskov Substitution Principle? In this series we talk about the SOLID design principles.
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[@MrWilde]

I have been watching online training videos for more than 15 years and the you can spot a great teacher when they have as much energy and enthusiasm as you do. Fantastic video

[@KawsarJami]

I fully understood LSP when you said on 10:57 "they're trying to show us when we should not use Inheritance and when we shouldn't"

[@abdullahbhojani4772]

exactly!

[@linjustek]

So the quote states, that we shouldn't use inheritance :D Or there is an error. :D. LSP is says that we should adhere to method argument and return types, when using implementation or when extending abstract declarations or overrides. Usually when you do not do that, but implement Interface with type declarations you get Type Error. 🙂 And we have to understand that type declaration can be abstract or interface, so child classes can be a fit for as an argument or return type.

[@McSeeMo_]

I imagine with the actual viral context you may have spare time to continue this series ! The crowd ask for it!

[@NdamuleloNemakh]

So basically it's, "whatever the parent can do, the descendants should be able to do that [and more]"?

[@MilaBarross]

Omg, thanks a lot!

[@lordmorgoth7]

it's, "whatever the parent can do, the descendants should at least be able to do that"

[@karthikeyancseskcet]

@@lordmorgoth7 great words

[@soumavanag5025]

@@lordmorgoth7 golden words

[@ipodtouch470]

Yes but the big caveat is just because the child must do what the parent is able to do does not mean the child has to do it in the same fashion

[@waelsalama84]

Hey Christopher, Hope you're very fine! I got shocked why did you stop this serious.. where are other parts..?? You're awesome teacher and really you've the skill of explain things in a very clear and easy way.. please don't stop producing these kinds of videos. waiting for other parts .. really in a big need to them .. really appreciate your efforts .. Keep it up!

[@SakethSusarla]

unique perspective and wonderful deconstruction, thanks for sharing :) it's 2020, still waiting for part 2...

[@ringoaikocascade]

I am so excited for the part 2. Especially for the past several years I've been avoiding variance, covariance etc and could really use his intuitive explanation.

[@michor10]

Yup, we're all waiting for the rest.

[@jfilipcic]

Still waiting

Is part 2 ever coming? We are all looking forward to it!

[@davidzhou9834]

It's 2022

[@radu5log76]

Thank you. You have really helped me understand Design Patterns and now SOLID. You are not assuming we know what you're talking about and that really helps get your knowledge across.

[@ChristopherOkhravi]

Thanks! Your comment is super helpful :) Much appreciated :) Thanks for watching and for the feedback :)

[@Vendavalez]

This is one of the best explanations for this principle that I have been able to find out there. For many of them I would walk away feeling like I understood everything that was being said, but not like a I learned something that I could apply, let alone ideas on how to apply it. I would love for this series to be completed if you have the chance or for you to address the topic as part of another series.

[@RocckeFella]

Bro you are doing a really good job. I really love the way you explain things.. more power to you.

[@davidecullen1]

Thank you! You helped me understand this principle the day before an interview!!

[@kinvain]

Wow! It takes you only 16 minutes to explain me Liskov principle and finally I can understand it. You are simply amazing!

[@jctkc]

You are the best man!! I've watched all your videos about Design Patterns and now I'm watching this and your explanation is simply great!. Thanks a lot!

[@shiblimohammadarafat6602]

It's indeed a great lecture! I have been trying to understand Liskov's Substitution Principle for a long time. Obviously I had some understandings which is correct but I also had some confusions as well. But your explanation is so clear that now I don't have any confusion about it. Thank you so much.

[@tsvetanpetrov5971]

Amazing! Usually, this is one of the hardest questions during interviews. Thank you for the hard work!

[@lda573]

When you started to use different colors, Evrika! LSP started to make sense! good job! thank you

[@RamKumar-kv1fx]

I though I knew Liskov's Substitution Principle for around a year but its only today I understand it correctly. Thank you very much Christopher Okhravi

[@c4stus]

Great as always Christopher, love your videos and your way of explaining stuff, don't stop please :)

[@yawar110]

Gist: The subtype MUST be able to do what its base type can do - Excellent clip! Keep posting good stuff.

[@sunnyshekhar862]

Just discovered your channel... And my my, What a fine job you have done explaining these concepts. I am from a non-Computer Science Background and even I was able to understand the logic in one go !! Seems like it's been more than an year that you did the 1st episode... Not sure why you dropped the Series... but like me many would love to see the 2nd and subsequent episodes in this series. 😇

[@0xlilx0]

Great explanation! Been reading about it for an hour and nothing made sense, but your video made it clear :)

[@guzideesra4743]

I swear, you should be the Dean of my University. Thank you a lot Mister Bean

[@StuartLoria]

When I study I vocalize my ideas similar to how Christopher conducts his presentations. I love the demystification of concepts in order to allow more people to get the job done, and enjoy engineering, no reason to be selfish or arrogant, these youtubers are fighting the good fight I think.

[@ChristopherOkhravi]

💛💛

[@marcodallaba]

Please continue this series, you're awesome!

[@irgatyus3090]

Thanks a lot man for your visionary approach. I'm about to get my dream job thanks to your educational channel. Keep up the good work.

[@ChristopherOkhravi]

Wow! Thats cool! Congratulations for the new job! 🙂🙂

[@asharnavya]

Really great way of teaching the things, i loved to learn from you.

[@giveexamples]

Learn the most difficult things while your brain stopped and doesn't work with Cristopher's magical videos. Thank you man.

[@MultiPauwel]

Top Notch explanation, i'm not a native english speaker and i followed some guides on PluralSight, came here because i still didn't get. Now i heared u talking, it's darn simpel, once u get it! Thanks alot!

[@volkancoskun6934]

This is excellent. I look forward to new part. You're awesome

[@MontagoDK]

part 2 ?

[@bananek131]

+1

[@sebastianvera5830]

+1

[@abderrahimouakki6734]

+1

[@pparturo2007]

+1

[@yevheniisemendiak2501]

+1

[@ooredroxoo]

The funny thing is that you had a video on Liskov Substitution Principle posted on July 2016, that was the video that made me discovery your channel.

[@ChristopherOkhravi]

Haha :) Awesome! Super thanks for sticking around :D :D

[@abhilashbandi3866]

Thanks for this :) I believe understanding SOLID will help in understanding Design patterns a lot better.

[@ChristopherOkhravi]

Thanks! I’m glad to hear :) It’s all connected indeed! :)

[@harishnamjoshi]

Chris you are a savior. Just love you videos. Waiting for next episode. 👍

[@iwanttolearn8939]

Thank you sir! :) I'll share this with my friends. very helpful.

[@ChristopherOkhravi]

Yeehaw! Thank you very much :) And thank you for watching :)

[@raymondho2]

Thank you so much! This is a great video to explain horrible LSP and really helped me to understand it :)

[@zbigniewcwiakalski7253]

Ech. That would be super cool to hear more about this in the next episode .... Hope it's going to be created eventually ;) regards

[@Erdling123]

Not only a great explanation, this was entertaining as well.

[@suhas002]

Great work man .. you are making things easy to understand.. waiting for other principles ..

[@aymanshaawat]

I really hope that you continue this series. Or at least start a new one talking about the same topic.

[@mikemihay]

Thank you! Please continue the tutorials!

[@soufrk]

Really makes it's simpler to understand !! Way to go

[@ChristopherOkhravi]

Thanks! I’m glad to hear :)

[@shaimaaaltaay5183]

OMG thank you so much I have an exam on Wednesday and I was lost with LSP principle.... I never enjoyed a lesson this much before thank you again

[@ChristopherOkhravi]

Aha. Great stuff :) How convenient :) :) Best of luck on the exam! 👍👍

[@shaimaaaltaay5183]

Christopher Okhravi I explained LSP to my friends before exam and they were like “oh that’s it 😮 it’s so easy” and I was like “yeah can you imagine “ and then gave them the link to your KZbin channel 😁 BTW DIP came in the exam not LSP 😂 except that scenario question with classes and DIP example I think I did well

[@theisegeberg]

While watching your design patterns videos (I watched all of them, all of the way through..) - I wished that you would do the SOLID principles as well, and here we are :)

[@DominikRoszkowski]

Great, clear and funny as always! Thanks a lot

[@TheLifeRockss]

2018 almost finished.. still no part 2? you can't do that to us mate :-)... Imagine Game of Thrones not releasing season 8

[@hiteshchalise3988]

now after watching season 8, I wish they didn't released it. lol

[@avnishsinghtomar7783]

we would have lived without season 8.

[@reyazahmed9320]

Please do the other parts Christopher. You are awesome!

[@vunguyenhoang3704]

really hope to see the next part. You are amazing broo

[@swatisingh8399]

All your explanations are so good and simple , its like listening to a story , so interesting , although I see you don't have a part 2 for this :( , requested by a lot of users

[@B-Billy]

Woow... That was awesome Please keep it up.. Great job And yeah, thanks for sharing. BTW, I missed that cat 🐈 LOL

[@kevinbenavides92]

Thank you Chris. Please continue this series on the SOLID principle if possible. Your the best.

[@ChristopherOkhravi]

Thanks! Will do :) Thanks for watching :)

[@UrzaRage778]

You're fantastic at explaining things! (Much like Tim Corey) - where'd you go?!

[@IlyaShap]

Wow! You’re an awesome teacher. Thank you so much!

Hi Chris. Thanks for all your videos. You have the skill to explain complex things easily. Do you plan to make a video about open close principle ?

[@rupn9633]

Very Unique way of explanation, I have see many videos on SOLID principles , this one standout. Great!!!

[@janabodu3392]

Mr Bean mastered design principles and became Christopher Okhravi...Great Explanation ...Thank you..

[@babindakistvan]

Thank you so much, really nice job!

[@Mochilador]

You rock! Thank you for these videos!

[@farzinfaghirnavaz1027]

You are incredible, thanks for your time please keep it up

[@ChristopherOkhravi]

And thank *you* very much for watching :) :)

[@ireneuszzagan9725]

Reaaaaaally want to see the next episde :)

[@jg5645]

Chris

[@a.rohimsama7222]

Yeah, the same here I like him.

[@aymanshaawat]

Your videos are great Waiting for the rest of the playlist

[@ChristopherOkhravi]

Glad to hear :) New design patterns video coming Monday but after that hopefully another LSP video. Thanks for watching :)

[@aymanshaawat]

Christopher Okhravi That is also good I am following the design pattern playlist too xD

[@user-yi4zd6gh5h]

the best explanation pf lsp. Please return to make these videos. You are one of the best teacher on youtube

[@cetiah]

I just recently learned from one of your videos that the snail would speak, but it would have a NullSpeaking behavior that's returned when you run Speak() on the snail.

[@salmanahmedkhan3979]

Preparing for exam and this masterpiece is pop up. Great Explanation

[@johnconnor9787]

Please continue making these videos!)

[@tejeshB19]

Amazing explanation !! Thanks a lot :)

[@MrVankog]

Great topic for a new series!

[@ChristopherOkhravi]

Thanks! I’m glad the topic is appreciated :)

[@PurpleSplash24]

Excellent explanation. Eagerly waiting for videos on remaining 4 principles.

[@georgebockari289]

I'd really love to see you pick this back up.

[@taskapptaskapp3138]

You are great man. You should have more views. I wish you all the best, greetings from Poland. :)

[@yogini1351]

Hello Christoph, You are awesome. I think I have watched almost all of your sessions on design patterns. This one is also amazing and simplified, but I didn't find the part 2 in this playlist. Could you please help with quick link?

[@jeffdosser4251]

Your vids are great. More ppl should be watching them.

[@danielmilewski7659]

cannot wait for part 2 !!!!

[@mufizshaikh8439]

It was very easy to understand with the help of your video. Thank you

[@opsherx]

this guy is so excited hahah thank you man

[@naito016]

2020 year, after a lot of videos listening blah blah and blah about Liskov's Substitution, finally understand the Liskov Substitution Principle then I Think this video was awesome need the next one, it's pretty weird that KZbin is not showing part two on following video, go to authors channel, looking for the part two that never comes.

[@saurabhsuman4960]

You are amazing. I love the way you explain. 👌

[@soniajain07]

you rock! Looking forward for your pat2

[@pawekrzyzak4345]

I have still waited for the next one!

[@josiahtobas9172]

Great explanation, thanks a lot.

[@cschandragiri]

Keep going on SOLID principles. Great expressions at 5:36 :)

[@cehdmoy]

Break Liskov is too easy, that's another reason because we should not use inheritance just for "reuse" code porpuse. Well if you know what are u doing, please feel free to use inheritance. But even Efective Java encurage developer to prefer composition instead of inheritance. My point is when we use inheritance IMHO we are so naive and we think that we can handle it, but finally we get a dog that acts like a airplane (LOL) and we have broken Liskov.

[@alecc8231]

Thank you Roberto. That's quick and easy to understand. If inheriting from dog you end up with an airplane = breaking of the Liskov's substitution principle. Quick and easy to remember. LOL. From now on I'm going to use your explanation.

[@nitingupta1989]

Hi Chris, The content is really good and helpful in understanding the intricacies of software design. Are you going to publish more videos on SOLID principles? Thanks :)

[@AustinCS]

Yea, I definitely need the second part lol

[@ronironion]

Awesome man! So easily served!

[@hana-games]

part 2 to save my life

[@dantesp7557]

Hey awesome explanation man, I have just started with code architectures and agile coding and have been able to get a grip on OOD just because of your channel big thanks for that and I have started recommending to everyone at my university who are interested in code architecture :D I also have a tiny requestm, if at all possible, I am presently looking at data oriented design approach... I am planning my carrer in gaming industry (programming obviously ;) ) and recently discovered issues regarding cache miss and other low level cost and with data oriented design architecture stating that it can be used to write high performance code specially for games. I searched and went through many resources but I cant seem to wrap my head around it. Many veteran programmers seem to know this by experience but since I am a novice I am unable to figure out whats happening or how to structure the data acc to DOD rather than OOAD... If you could share a little light on it then would be great... thanks again for bringing agility to my code :D :D

[@cepi24]

Sir you are doing great job and seems you are enjoying it

[@AdrianBlogs]

I like your way of speaking you also speak English very well and I understand what you say

[@meetrjsingh]

Thank you for the wonderful explanation

[@rubenbasketpalencia]

You can also talk about he exception throwing. A subclass mustn't throw an exception that it superclass can not throw. (correct me if I am wrong) Thanks for your videos!

[@aprendemusica1931]

Love his passion teaching 💞

[@tusherkhan7531]

Thanks for making it easy!

[@felipeignaciocastrojara5065]

THANKS bro, love from Chile!

[@ruioliveira2230]

Will you ever finish this series? Good job on the Patterns playlist

[@asharnavya]

I am waiting for you next part of this series. When you are going to post ?

[@rohitkalya]

Hi Chrisopher, Can you please post the 2nd part of this video.

[@divyeshkumarbalar7732]

its been 4 years since i commented, still waiting for part 2 :)

[@sergiubarsa1607]

Great video. Are you planning on releasing more SOLID-related videos?

[@wassimmehanna4402]

Any chance that you could do a continuation for that video ? Many thanks!

[@djordjepetrovic2365]

Great lecture, thank you!

[@mrinaldhawan3959]

Great videos man! Complete this series. I have already watched the Code Walks of SOLID. This came to my mind while watching this video. Not sure if this is a correct analogy! At 14:17 when Chris holds the RED and GREEN Markers on screen, We believe that GREEN is Subtype of RED. Lets suppose the Marker Caps are properties of the Markers. If we remove the Cap from RED and replace it with GREEN marker cap, it should fit perfectly as GREEN is truly subtype of RED.