Two's Complement | PicoCTF 2017 [38] Guess The Number

[@lucky179009]

Best explanation of two's compliment i've heard. Going to use your method from now on lol

[@60NoyCoolUser]

Great video. I solved it and needed an explanation. Your video was exactly what I needed. Thanks!

[@_JohnHammond]

Happy to hear it, thanks for watching! :D

[@anuragdeep3367]

There is an even simpler method to get two's complement. Starting from least significant bit keep the value of the bits unchanged until you reach the first '1' and after that flip all the bits including the sign bit. Eg:- 0110->1010

[@_JohnHammond]

NICE! This works great, thanks!

[@anuragdeep3367]

Thank you sir

[@matthewreed2000]

I'm no expert, but I believe that the reason 32-bit ints are maxed at 2^31 is because there are 2^31 positive ints and 2^31 negative ints. 2^31 + 2^31 = 2(2^31) = 2^32

[@_JohnHammond]

More expert than me :P Good to know, thank you!!

[@wecksell]

Exactly, one bit kind of becomes your sign indicator.

[@wecksell]

You want to try the operator xor, ^ in most languages, python: 0b0110^0b0101 A little easier than your replace method. Thanks for your videos, I have learnt alot from them!

[@altf4thc]

why cant we push win on the stack and ret like we do in shells?

[@zanidd]

Cool use of something rather boring I had to learn for school. Nice to know that the stuff I'm learning at school can be used in ctfs xD

[@_JohnHammond]

VERY RARELY, but sometimes there are crossovers xP