Interview Questions on Concurrency, GCD, Operation Queue | Swift (Mastering Concurrency in iOS - 6)

[@mattheaney729]

Thanks Pallav, this is an incredible series! I picked up so much info on just a watch through, but i'm looking forward to going back through to really lock my understanding of these concepts in. Keep up the awesome work with the videos!

[@VinayGupta-vz9od]

This mastering concurrency series is awesome. Along with this your mock interview series is too good, in all iCode helped me crack 3 companies and I was able to switch my job and get my concepts crystal clear. Thanks a lot !! 🙏❤️🍎👏

[@iCode_Happy_Coding]

Congratulations Vinay, and glad to hear that you found the videos helpful 🙂

[@sumitguptasg1]

I couldn't find the iOS data persistence playlist on your channel, if not already created would you consider it next? Thanks.

[@MajdurDancer]

Omg❤ i have started following you, and each and every video is too good to understand. please upload more videos on unit test cases and more tutorials on iOS interviews. It helps the developers like us❤

[@sifatulislam7357]

I gotta say, your stuff is seriously awesome. It would be even more awesome if we could have more topics on concurrency explored, such as async-sequence, async-stream, async publisher, detached task, continuation, and so on.

[@princepushkraj]

Amazing series buddy, you always make things pretty simple 😀

[@keerthichinivar5997]

This is an excellent series I have come across with respect to Concurrency in iO. loved your dedication in covering the details of all the concepts. Looking forward for your upcoming video. I have a request for you: Can you please do a similar video for Core Data? Encryption of core data, accessing it. Relationship , delete rules and concurrency

[@rj007love]

@icode - Make more videos , you are a true Gem, You helped many to get good packages in big companies. Kindly create more videos regularly.

[@iCode_Happy_Coding]

The interview series has been released, please have a look 🙂

[@sandeep19831000]

thanks, Pallav for such great content. Using a sample Xcode project(No Playground) with NSLog would be great instead of print. NSlog will clarify which thread is used for which code block or which piece of code is executed on which thread. Any specific reason for using the playground? Meanwhile the output of code used at 4:08 is below, using Xcode project with NSog. its clearly show that async is being executed on a different thread. 2022-11-17 16:27:54.641339+0530 ConCurrencyTest1[58676:405361] 50 51 52 53 54 55 2022-11-17 16:27:54.641878+0530 ConCurrencyTest1[58676:405361] 30 31 32 33 34 35 2022-11-17 16:27:54.641884+0530 ConCurrencyTest1[58676:405430] 10 11 12 13 14 15 // queue.async 2022-11-17 16:27:54.642591+0530 ConCurrencyTest1[58676:405430] 0 1 2 3 4 5 // queue.async

[@namanjain6153]

Pallav, have a doubt, at 4:50 , u told that you are unsure and it is unpredictable to say what will be printed first between 0 to 5 and 10 to 15, but why, here complexity is same, so 10 to 15 should also end first, and queue is FIFO, so why 10 to 15 is not printed first always?

[@poonamyadav-qz7yt]

Hi Pallav, I did not understand why 10..15 will be printed before 0..5? both of them are serial queue and async. so it could be possible that second queues finishes executions of all task first and hence dequed before the first queue and can be printed first. where am I going wrong in my understanding?

[@kelvinfok]

Thank you! The quality of your content is top notch 🎉

[@nickpatel1663]

4:51, how you will sure that 0 to 5 must be printed before 10 to15 always as it is async block with concurrent queue?

[@roh9934]

he said "can". both of the possibilities are there.

[@reddybharadwaj324]

Thanks for the content it was on point but there are actually no videos in past months so just wanted to know out of curiosity are you stooping it here or will you start it again it would be great to see your videos again

[@iCode_Happy_Coding]

The interview series has been released, please have a look 🙂

[@reddybharadwaj324]

@@iCode_Happy_Coding yeah the series is pretty good as well and to begin with your old interview series helped me get a job as an iOS Dev.

[@anurantheassassin]

Thanks for the video. Will appreciate if same could be done for Core Animation.

[@priyeshp1737]

Think of a serial queue as a single-lane road. On this road, cars (tasks) can only move one after the other. Only when the car in front has reached its destination (task has completed), can the next car start moving (next task can start). On the other hand, a concurrent queue can be thought of as a multi-lane highway. On this highway, multiple cars (tasks) can move forward at the same time, each in its own lane. They don't have to wait for the car in front to reach its destination (task to complete) before they can start moving (task can start). Now, consider synchronous (sync) and asynchronous (async) operations as traffic signals. A synchronous operation is like a red traffic signal. When it is encountered, all cars (tasks) must stop and wait until the operation is complete before they can continue(People crossing the road). An asynchronous operation, on the other hand, is like a green traffic signal. When it is encountered, cars (tasks) can continue moving without having to stop, even if the operation is still in progress(Some road work). Basic idea can be inferred from the above comparison.

[@sambhajihajare8720]

Best videos on concurrency ❤️

[@luckymehndiratta4511]

Greetings of the day Can you please suggest me a good book for value type and reference type concept in more details. Why there is only these two type reference and where is the start point of these two

[@kavyashreehegde6643]

Thanks!

[@manjeetchoudhary5860]

Very helpful videos thank you 🙏 🎉

[@iCode_Happy_Coding]

Glad it was helpful!

[@manjeetchoudhary5860]

You are genius❤

[@maqusss]

Here is a question: whats wrong with code at 8:05 ?

[@roh9934]

what do you think?

[@kareemfekry305]

Brilliant

[@jur9103]

Glad we now have Tasks, Actors, await, async, swift algoritms..yeah old times..

[@harshit2629]

:-)🙂🥰

[@Viratkohli-hu6bm]

Thanks pallav!

[@victorriurean]

[@RaviRanjan-xl7fk]

Yesterday I have being asked This DispatchQueue.main.async { print(123) DispatchQueue.main.sync { print(456) } print(789) } My answer was: 123 Reason: that main queue was not free as the asynchronous block was computing it self. Can you please clear more on this?

[@maqusss]

Your example has deadlock after printing 123. In docs for sync method: "Calling this function and targeting the current queue results in deadlock"

[@roh9934]

Bro, which company asked such question? solution is when .sync closure will be called on Main Thread, it will lock the Main Thread & search for other Thread to execute the task, The Scheduling Algorithm is designed in such a way that, it will only come back to Main Thread (which is locked) & no task can be performed in it. So, in a way, The task inside the .sync closure will never execute & in fact Deadlock will happen. However, if you run other code For eg: 789 outside the async call it will execute maybe ( Have to check which Thread is running the 789 statement ( Most probably Background Thread).

[@ConernicusRex]

This is terrible code. You locked the main thread.

[@michaeljfransen]

Thanks!