Ask Ubuntu General Room

2:24 AM

@PerlDuck Thank you for that by the way! I think though that really either they are one in the same person, or they know each other extremely well. The other question that is linked was getting the same 2 people on it with the same non-sense type answer getting instant upvotes. It is good that the question has been closed as a dup now. Looks like those 2 are getting a fair share of downvotes on both of those questions.

@Fabby I am thinking I need to steal that canned response. That exact thing with the comments then someone taking my comments and building their answer from the work I did happened to me over 3 years ago. Somehow people just like stealing my work and passing it off as their own. =)

TheWanderer

3:05 AM

so what's the point of using pointers in cpp?

Seth

3:51 AM

So you can pass by reference

Ubuntu Questions on U&L

0

Q: How to compare bash variable with double quotes

I have this code STATUS=`echo "test"` if [ $STATUS == "test" ]; then exit 0 fi I have tried everything and i am not able to make it true. I tried "$STATUS" == "test" eval $STATUS == "test" ${STATUS[@]} == "test" THE only thing taht worked is $STATUS == \"test\"

TheWanderer

@Seth I don't know cpp

at all

Seth

obvs :P

lemme throw up a quick example.

TheWanderer

if I'm reading this right though, you can pass a primitive variable like an int as *variable to a function

and if you reassign it in that function, it'll also change the original variable

kind of like changing properties of a passed Object in Java?

Seth

@TheWanderer eeek I haven't done Java in so long. Or cpp for that matter but I've done some go sorta recently and we use pointers there too.

TheWanderer

4:03 AM

in Java you can do this

void someFunction() {
    SomeClass variable = new SomeClass();
    otherFunction(variable):
    int theValue = variable.someField; //this will be 1
}

void otherFunction(SomeClass variable) {
    variable.someField = 1;
}

Seth

right

You'd need pointers in cpp to do that

TheWanderer

ah OK

Java doesn't quite let you do what cpp can though

like I couldn't just pass the object and then reassign it in otherFunction()

Seth

think of it kinda like a scope thing right.

Videonauth

I told you already, Java is an island where no one plans vacations to ;P

Seth

it's not really scope but you can think of it that way.

TheWanderer

4:06 AM

scope?

@Videonauth I use Kotlin

lambdas in JRE 7 woot woot

Seth

@TheWanderer e.g if you assign a variable in one function its scope is only inside that function

TheWanderer

yeah

so cpp basically lets you bypass that without member variables

Videonauth

exactly

as well you can do math with pointers

Seth

yeah

Videonauth

as i told you in discord, if you have a pointer to an array of values you can give that to your function and even iterate over more values as only the first

int for example is 8 byte

so you can get the second array value by adding 8 to the pointer value

and so on

Seth

4:09 AM

oh yeah the discord exists. I should lurk there more.

TheWanderer

no this was a DM

I need to actually learn cpp

so much of Android is written in it

Videonauth

ah and before someone kills me for not mentioning, the sizes of int long etc can differ on the different platforms, so better use sizeof() instead of fix values

IRRC sizeof() is in <types>

Seth

@TheWanderer I don't know any good resources unfortunately :/

Nathan might.

learncpp.com seemed decent when I was reading it before but idk. YMMV

TheWanderer

so what's a quick diff on int32_t vs int?

Videonauth

sec.

TheWanderer

4:15 AM

are int32_t s = 1 and int s = 1 the same?

Videonauth

@TheWanderer int32_t is typefixed

TheWanderer

but what does that mean

Videonauth

while int maybe somewhen in the future longer as 8 byte

or 64 bit

maybe you have an 128 bit system

TheWanderer

how do you know how many bits an int has?

Videonauth

int32 is 4 byte

or 32 bit

TheWanderer

4:16 AM

or is?

just convert to binary?

Videonauth

learn your powers of two :)

1 byte = 8 bits

TheWanderer

no I'm asking how many bits an int has

Videonauth

normally as far i remember on windows and linux the same size, 8 byte

so 64 bits

00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 to 11111111 11111111 11111111 11111111 11111111 11111111 11111111 11111111 in binary

64²-1

in max value if unsigned

TheWanderer

so how many bits is 1?

Videonauth

00......01

TheWanderer

4:20 AM

so 1

so the answer is yes, you convert the int value to binary to see what bit count it is

Videonauth

no 2 is for example 000.....010 (binary shortened)

3 is 000...011

so two is only one bit too

TheWanderer

ugh

can I just use int and not worry about the int32 and int8

Videonauth

well the mx possible number is differnt between those two

int8 has max 256 as value

or if you count zero 8²-1

TheWanderer

but why would I need that?

Videonauth

int8 is equivalent to short

to save memory

TheWanderer

4:24 AM

ohh

there we go

so if I know that int won't go above 8-bit, I can use int8 and save 24 bits

Videonauth

if you know you only have a certain value for something you can use smaller yes

you save in modern systems not only 24 bit

its 56 bits you save

TheWanderer

I mean compared to an int32

so int is limited to your architecture

Videonauth

theres an int64_t which is in most 64 bit systems the equivalent of int

TheWanderer

on an 8-bit system, int would be the same as int8?

Videonauth

yep

TheWanderer

4:26 AM

yep

alright I get it now

Videonauth

this is what the sizeof function is for

TheWanderer

that returns the bit-count?

or the int value?

Videonauth

the byte size

std::cout >> sizeof(int) >> std::endl

try it

should output 8

TheWanderer

I don't actually have an 8-bit system lol

Videonauth

no on a 64 bit system

TheWanderer

4:28 AM

nor do I have a cpp environment set up

why would it be 8?

Videonauth

8 byte == 64 bit

TheWanderer

oh derp

byte

it's 12:30AM lol

I'm building Android and doing chemistry

Videonauth

:)

well i have to admit I'm not the best to put this knowledge into English words :)

theres one good site for cpp tho let me find the bookmark

cplusplus.com

good as refernece and their tutorials are good too

TheWanderer

that site looks like it was made soon after the invention of cpp :p

Videonauth

I will send you an email with more material tho

@TheWanderer well its not nice but it has all the referneces for every cpp command

ok might now very well fit into a mail lol, give me a second

do not think gmail will accept 300 MB mails

:D

will give you a link in discord tho

Zanna

5:51 AM

@PerlDuck I'm happy you found something good to eat in London! It's definitely possible to do, but significantly easier to avoid XD

also, surprised they were on German TV haha

@Terrance yeah, see a bit about that from this message.

dessert

6:55 AM

Could someone please dupevote this? See my comment: askubuntu.com/q/1050599/507051

Zanna

7:12 AM

done :)

Fabby

7:50 AM

@Terrance It's all yours!

@dessert final vote. Closed.

dessert

thank you!

lol, I love VIM:

> Place your cursor over the first dot (in .star10) and type the following in normal mode: qa3yy3jp^Xjt;18^Xk0q

from here: stackoverflow.com/questions/4951533/…

Zanna

8:07 AM

PS @dessert there's no need to keep the original when doing a translation... it's considered noise

dessert

It is? I thought I read about it on meta…

Zanna

oh yeah?

dessert

here:

> Don't remove the native version, just write the English translation above it with a notice so that people understand that it may be inaccurate.

23

A: What to do with non-English questions or answers?

Localisation has been discussed before but speaking about this question right now, we really only support English. That said, this is still somebody who needs help. Closing something just because of its language should be a last resort. Ubuntu is global and we should expect that, as the best Ubu...

still your edit is totally fine though!

I only used google translate and not my superior language skills (I hate translating!), I think it’s a good thing to leave the original there in cases like that. However, if you approved of the English version that’s reason enough to remove the original IMO.

it’s very unlikely relevant information got lost after all

Zanna

oh ok... I think there is another meta post saying take it out

I know some Portuguese and I know English :)

Fabby

That is good advice to people who're not multi-lingual... I've translated things where the translation was actually better than the original, so leaving the confusing original in does not make any sense...

Zanna

8:20 AM

is it just me, or are Ask Ubuntu questions an incredibly easy text type to translate? I can understand Ask Ubuntu posts in languages I know barely anything of. If I know the language at all, it's a breeze!

thanks @dessert for finding the post, I appreciate that :)

in 2016, I think we made a g-sheet or something of people with language skills willing to do translations

Fabby

@Zanna That's because you're a genius! ;-)

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