For a database, the only important thing about time is that 1/ simultaneity doesn't exist 2/ time is steady

oh okay, tbh, we should just come up with a better solution to get time into a number

TAI and GPS time kinda solve that

but you cannot rely a lot on time unless you own an atomic clock or a gps clock and networking hardware capable of a PTP synchronization

the perfect solution to everything, binary time, "will it happen?" or "did it happen?"

It may be hard to realize, but the time light takes to go 1km is enough to complete a trading transaction in a financial quotation engine

Just by having a 2m DVI cable makes it impossible for your computer to display nanosecond accurate time

it will always be off by at least 6ns, the time needed to go through that cable

I cannot uphold any time constraints in my database engine except the following: time goes forward

Just by having a 2m DVI cable makes it impossible for your computer to display nanosecond accurate time

most display panels are 60hz so youre off (in the worst case) by 1/60s

most display panels are 60hz so youre off (in the worst case) by 1/60s

I meant even in the case you had a mathematically perfect object as a screen

true, but tbh, why would you want such "perfection"

a human being couldnt tell any accurate time below 100ms

What i mean to express is that computer science is one of the very few fields where you literally have to deal with relativistic effects, as such, never under estimate time

youre right, but at some pont you start overengineering things

most of the time you work with some kind of analogy for example you want to measure some kind of distance between some things, where on earth would you need ultra perfect precision to idk the 50st digit

At some point you may have to say which, of two transactions that came at about the same nanosecond, happened first and who will be able to buy something when it is cheap leaving the other in the dirt

practically, it wont matter if you use pi with 50 digit accuracy or 100 digit accuracy

if youre doing some kind of manufacturing

To quote Andrei Alexandrescu: "Write your code like you are going to defend it before court because that may happen some day"

practically, it wont matter if you use pi with 50 digit accuracy or 100 digit accuracy

Well, floating point calculations are by design very imprecise when you are out of -1 <x < 1

thats not what im about

Sometimes accuracy is important

there are for sure ways of actually using some number up to the 50st digit

Do you know what happens in my database if two transactions happen "at the same time" for example ?

nope, but im certain you will tell me 😏

Nothing

It is the very only case where the database doesn't make progress on processing

so you just reject both?

so you just reject both?

Can I accept any and remain correct ?

id just take whatever i received first

id just take whatever i received first

How do I know which I received "first" if both have the same time ?

how does your networking work?

just take whatever comes in first

just take whatever comes in first

You don't understand the issue, yes, you receive transactions in an "order", but you have to uphold to ACID constraints, and the very idea of simultaneity breaks linearizability. you need to write data in a form of order, and this order have to prove the order of operations. Not dictate it, prove it. if one of the transactions succeeds and someone loses big bucks because he was not "chosen" first, you have not written a fair concensus and linearization

When I say you may advocate your decisions facing a court, it is quite literal if you work for a multinaional financial institution or if you make software used by them

as there a nanosecond can mean an empire

interesting, but how do you actually get like the time you received something

In finance it often happens they use network hardware that stamps packets with times synchronized with an atomic clock using PTP with a sub nanosecond accuracy

because you have to be able to say: "this man was first on the deal"

And to be able to prove it

Simultaneity must be, like in nature, an impossibility

To quote Joe Armstrong (may he rest in peace): "I am a physicist at heart, as such I must write computer systems that respect the laws of physics"

who do i remove the "\n" that fgets add when input a string(array of char's)

Is anybody know how to move my cursor into Line7 automatically after creating a demo.c file in Clion?

$END doesn't work.

no one will teach you how to connect these things, you must understand yourself

working with db connection in c -> google

Hello

Welcome

Cout << pow(2,5) isnot running 😥

#include <cmaths > was also used

'cmath' not 'cmaths'

'cmath' not 'cmaths'

Yes I have used <cmath> 😅

Already but then also

did you link math libs?

No

Then link it

Cout << pow(2,5) isnot running 😥

not running but doing WHAT?

not running but doing WHAT?

Invalid directive showing

Hi Administrator, a friend is trying to join this channel and it says "sorry this chat is no longer accessible"

<math.h>. Was the right thing to be used and it runs fine now

Ban lol

Hi Administrator, a friend is trying to join this channel and it says "sorry this chat is no longer accessible"

Give id

@danielg_hornik

@danielg_hornik

Hm no idea

@K11M1 he remembered... apparently he posted a picture with his laptop sticker

Ban lol

Oh wait

I dont Remember and havent find him in logs

what happened

<math.h>. Was the right thing to be used and it runs fine now

pow must be std::pow in this case

pow must be std::pow in this case

There is using namesapce std

There is using namesapce std

OK I give up!

https://ideone.com/MPWBQM

This is my code for adding two polynomials please tell me why on input of 5x^3 and 6x^2 is giving me only 5x^3

Hi guys does anyone know a good place to search for C basic knowledge as I am trying to learn for my University?

Google

Hi guys does anyone know a good place to search for C basic knowledge as I am trying to learn for my University?

https://en.cppreference.com/w/c