The Whiteboard

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deostroll

01:31

@RobertHarvey I did. isn't that a library/tool? Yes, its opensource, but its not a mock implementation, easy to hack and learn...

Robert Harvey

@deostroll You have access to the same search tools we do.

@deostroll Try this: tls.mbed.org. It's designed for embedded devices, so it has a small code footprint.

In particular, this: github.com/ARMmbed/mbedtls/blob/master/programs/ssl/…

1 hour later…

Aaron Hall

02:57

Yay, my talk went well! I didn't totally embarrass myself!

1 hour later…

daOnlyBG

04:06

(anyone here?)

Robert Harvey

@AaronHall Any talk that you can walk away from is a good talk.

Or aircraft landing, whichever comes first.

9 hours later…

user143252

13:39

#include<stdio.h>
int main()
{
int i=3;
i= i++;
printf("%d",i++);

getch();
return 0;
}
what will be the output of above program and why

ratchet freak

@user143252 undefined

user143252

@ratchetfreak no ..

here is tiny modification ... #include<stdio.h>
int main()
{
int i=3;
i= i++;
printf("%d",i);

getch();
return 0;
}

ratchet freak

yes, the result is undefined because of the i=i++ line

user143252

i run the above code in devc++ and its not undefined @ratchetfreak

ratchet freak

A: is i=i++ truly a undefined behavior?

The phrase, "…the final value of i will be 4 no matter what the order of evaluation…" is incorrect. The compiler could emit the equivalent of this: i = 3; int tmp = i; ++i; i = tmp; or this: i = 3; ++i; i = i - 1; or this: i = 3; i = i; ++i; As to the definitions of terms, if the answer ...

"undefined behavior" can do anything from working as intended to blowing up your home

user143252

13:42

but what about devc++ result ???????

Thomas Owens

Undefined means that the language specification doesn't say what to do. A compiler needs to do something. If you used a different compiler, you may get a different result. Or even a diffeent version of the same compiler.

user143252

what i will answer if this question is asked in interview and there is no option like UNDEFINED.. what to do in that case ??

Telastyn

nobody uses devc++, and haven't for almost a decade.

ratchet freak

complain to the guy that made the interview

user143252

one more question ??? if i use any ide like devc++ or codeblock ... what is the different .. every ide is using gcc , so result will be the same in all case ide ...

is it ??

Thomas Owens

13:46

@user143252 If you are being interviewed by someone who claims to know C++ and doesn't know that it's undefined behavior, that would be a red flag.

ratchet freak

undefined is the only right answer in this case

@user143252 no because undefined behavior can change from one compile to the next

user143252

ok. @ThomasOwens red flag for me for interviewer ?

ratchet freak

@user143252 it means that the interviewer doesn't know C++ all that well

Thomas Owens

@user143252 For you. If I'm being asked such technical questions about language behavior, I expect the interviewer to know the right answer. If they don't, that doesn't give me confidence in the company or the people I'd be working with.

user143252

ok .. i got it.. thnks

codeblock & devc++ both is based on GCC , i am correct ? and both will produce same result

Thomas Owens

13:50

Like I said, it could vary depending on version of the compiler. Two versions of GCC may behave differently. There could be compile-time flags in GCC to change the behavior depending on OS. No matter what, you cannot rely on any undefined behavior being consistent.

ratchet freak

there could be surrounding code changing the behavior

user143252

one more question .... how to know which code is has undefined behavior and which don't ?

ratchet freak

knowing the spec

user143252

what spec?

ratchet freak

the language spec

user143252

13:55

thnks for the help :)

1 hour later…

Aaron Hall

15:15

Would that warn if compiled with -Wall?

(Of course I could just test it myself... :P)

You can do a here-doc into gcc, right?

$ gcc -xc -Wall - << EOF
> #include<stdio.h>
>  int main()
>  {
>  int i=3;
>  i= i++;
>  printf("%d",i++);
>
>  getch();
>  return 0;
>  }
> EOF
<stdin>: In function ‘main’:
<stdin>:5:3: warning: operation on ‘i’ may be undefined [-Wsequence-point]
<stdin>:8:2: warning: implicit declaration of function ‘getch’ [-Wimplicit-function-declaration]
/tmp/ccpjpvqz.o::(.text+0x41): undefined reference to `getch'
collect2: error: ld returned 1 exit status

And there you have it!

(Did I do that right?)

By the way I did that on Cygwin, maybe not the same as doing it on Linux...

Wikipedia can be wrong, but since it says I'm right, I'm inclined to agree with it.

2 hours later…

Duga

17:26

Maybe move to here: programmers.stackexchange.com — busfault 10 secs ago

Duga

17:57

I'd absolutely suggest references, As far as performance I'd rec. creating some type of local caching system and then getting each data when it's version is different than your own and updating it, perhaps through a subscription notification. That being said perhaps this isn't the best forum for this question, you may have better luck at programmers.stackexchange.com or the apple dev forums. — thefredelement 17 secs ago

enderland

18:21

-2

Q: Where to begin Python?

I would like to learn Python but have very little programming experience. In the past (many years) i've dabbled a little with C C# and Unix. ATM all I have access too is an ipad. I'm wondering what I will need to properly learn Python on ipad and what's considered the gold standard source for ...

python

lol

user143252

what is output and why #include <stdio.h>

int main() {
// int i = 1+2+3+4+5+6+7+8+9+10;

i = (3,4);
printf("%d",i);
return 0;
}

ignore comment

???

@AaronHall thnks

Robert Harvey

-6

Q: iOS Development in Berlin

I've been an iOS developer in London for the past few years. The contractor market in London is very much alive. I've recently moved to Berlin and I'm wondering how the contractor market is here, and the best way of forming a recruitment network. For example, are recruitment agencies an effectiv...

ios

Ack ack a dack

BOOM.

Aaron Hall

18:49

@user143252 I do not know C well enough to answer your questions with any kind of authority, but I can still attempt to compile code:

$ gcc -xc -Wall - << EOF
> #include <stdio.h>
>

>  int main() {
>  // int i = 1+2+3+4+5+6+7+8+9+10;
>
>  i = (3,4);
>  printf("%d",i);
>  return 0;
>  }
> EOF
<stdin>: In function ‘main’:
<stdin>:6:2: error: ‘i’ undeclared (first use in this function)
<stdin>:6:2: note: each undeclared identifier is reported only once for each function it appears in
<stdin>:6:8: warning: left-hand operand of comma expression has no effect [-Wunused-value]

@user143252 you need to learn to do this for yourself.

There's a C chatroom on Stackoverflow, you should ask your questions there. This site is about software engineering.

user143252

plz give the link for software link

software not chatroom

@AaronHall where is c chatroom of stackoverfloq

Aaron Hall

C

C stands for Control.

user143252

:( You must have 20 reputation on Stack Overflow to talk here

Aaron Hall

Then start building rep there. It's all about the sweet rep there.

I'm so close to rep-capping today! :D

user143252

19:05

ok thanks

Aaron Hall

19:19

shibboleet

Duga

19:33

This question may find better resolution on programmers.stackoverflow.com, but it's entirely a design choice on your part. There's no problem to solve here, you're simply asking for advice. — g.d.d.c 22 secs ago

Aaron Hall

yay, rep-capped! (I wonder if someone was serially upvoting today...)

Telastyn

+140 for me for one rando question.

Aaron Hall

link or it didn't happen

Q: Are single-character constants better than literals?

I have recently encountered a class which provides pretty much every single-character as a constant, everything from COMMA to BRACKET_OPEN. Wondering whether this was necessary, I read an "article" which suggests that it may be helpful to pull single-character literals into constants. So I'm skep...

programming-practices

A link makes it happen

Comma

The comma ( , ) is a punctuation mark that appears in several variants in various languages. It has the same shape as an apostrophe or single closing quotation mark in many typefaces, but it differs from them in being placed on the baseline of the text. Some typefaces render it as a small line, slightly curved or straight but inclined from the vertical, or with the appearance of a small, filled-in number 9. The comma is used in many contexts and languages, mainly for separating parts of a sentence such as clauses, and items in lists, particularly when there are three or more items listed. The word...

There are lots of different variants on commas: en.wikipedia.org/wiki/Comma#Comma_variants - perhaps this is not such a dumb idea, especially if your source code can be encoded as utf-8. — Aaron Hall 15 secs ago

Telastyn

20:09

right.

Aaron Hall

20:32

Unrep-capped. :(

Oh well. :)

Aaron Hall

21:27

I think we could salvage a lot of questions if we could migrate them to TEHCODEZ.SE.

Majiick

22:07

Hey guys, I just wanted to know if my question is fit for this site. I want to reverse-engineer an old game and document the process on my blog, how would employers look at that?

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