hey C[++] gurus! What does this code do...

[Darren Dirt]

the "#define" is where stuff gets real.


found via http://stackoverflow.com/questions/235848/most-astonishing-violation-of-the-principle-of-least-astonishment

[Lazybones]

found via http://stackoverflow.com/questions/235848/most-astonishing-violation-of-the-principle-of-least-astonishment

This question was removed from Stack Overflow for reasons of moderation. Please refer to the FAQ for possible explanations why a question might be removed.

[Thorin]

At first glance I thought I understood it.
At second glance, it looked a little complicated.
At third glance, MADNESS

[Mr. Analog]

Check the accepted answer: http://meta.stackoverflow.com/questions/27112/amusing-404-page-not-found-images-for-trilogy-sites

AND the comment (explains why this is on the 404 page for Stack Overflow)

EDIT: (hint: HTTP 404)

[Thorin]

Ah yes, those aren't #defines, as there's incorrect spacing in all three of them.  They're just all commented out (as is line 3).

[Tom]

Ah yes, those aren't #defines, as there's incorrect spacing in all three of them.  They're just all commented out (as is line 3).

Nope. You're allowed to have spaces before the command with the C preprocessor. So long as the text that follows is a cpp command. Otherwise it is just a comment of sorts.

[Thorin]

#<space>define
#<space><space><space>define

are not valid because there's a space between the # and "define".

#define/*>.@*/exit()

is not valid because there's no identifier

I'm not saying this won't compile, I'm saying lines 1, 2, 3, and 5 have no impact on what this code does.

[Mr. Analog]

Did anyone actually follow this link: http://meta.stackoverflow.com/a/27846

'cause seriously Perl/Python/Ruby/C/Befunge/BF

NOT C++

[Tom]

#<space>define
#<space><space><space>define

are not valid because there's a space between the # and "define".

#define/*>.@*/exit()

is not valid because there's no identifier

I'm not saying this won't compile, I'm saying lines 1, 2, 3, and 5 have no impact on what this code does.

Again, not true. You can have spaces between the # and the command name. It's 100% valid at least on GCC, and I assume VC++ as well.

Did anyone actually follow this link: http://meta.stackoverflow.com/a/27846

'cause seriously Perl/Python/Ruby/C/Befunge/BF

NOT C++

C++ is mostly a superset of C. So in this case, same difference. Both use the same preprocessor.

[Mr. Analog]

True, but I reckon Thorin is used to seeing MS Visual C++ not console C++

anywhoo FOLLOW DA LIMK

[Tom]

True, but I reckon Thorin is used to seeing MS Visual C++ not console C++

anywhoo FOLLOW DA LIMK

I did

[Mr. Analog]

cool cool

Also I just tried running this in C++ and got a compile error, but it went like bananas in C, and I got the expected output

[Tom]

cool cool

Also I just tried running this in C++ and got a compile error, but it went like bananas in C, and I got the expected output

Yeah, C++ probably doesn't like the lack of "int" before main, and the lack of parameters in main as well. () in C++ is the same as (void) in C. () in C is "unspecified" meaning it can take any number of parameters.

[Mr. Analog]

Yep, t'was a trip down memory lane... I haven't touched C++ in a while...

Also, best 404 message EVAR

[Lazybones]

Just for fun (since I don't have have a c compiler installed)

http://codepad.org/e1L959z5

[Thorin]

I clicked through the first link you posted and read the accepted answer (and a bunch of others,  interesting topic).  I've also now clicked through your second link, not realizing it was the accepted answer.

I don't believe I said anything about C++?

Also

Again, not true. You can have spaces between the # and the command name. It's 100% valid at least on GCC, and I assume VC++ as well.

if that is true then I learned something new today.

Every C (not C++) reference I read for preprocessor directives in the last 15 minutes says nothing about allowing spaces between # and define, neither whether it is allowed or not.

[Mr. Analog]

Well I assumed you were talking about C++ because very often when you see stuff defined there's no space "#define blah" you mentioned the space so I jumped to conclusions (on my special Jump to Conclusions Mat)

[Thorin]

Nice Lazy.  So in C the #defines are accepted and used, in Perl they're simply commented out.

Had to look up putchar (http://www.cplusplus.com/reference/clibrary/cstdio/putchar/) and then ASCII codes (http://ascii.cl/htmlcodes.htm) to see what those first two #defines do.

Still.  Barn.  Behind.  Beaten.

And I should borrow that mat of your sometime, I do it to

[Lazybones]

And I should borrow that mat of your sometime, I do it to

[Mr. Analog]

Well, now I know Thorin reads my posts all the way through LOL

[Darren Dirt]

So I didn't read the SO comments/discussion, but I did visit the http://codepad.org/ link and saw the output.

Whoever offered that as a suggestion for the 404 for the above-average-intelligence community of Stack Overflow: Way to make the over-thinkers of the world feel pretty dumb. Well played.

[Lazybones]

Well, now I know Thorin reads my posts all the way through LOL

Ok, I get it now.

[Mr. Analog]

So I didn't read the SO comments/discussion, but I did visit the http://codepad.org/ link and saw the output.

Whoever offered that as a suggestion for the 404 for the above-average-intelligence community of Stack Overflow: Way to make the over-thinkers of the world feel pretty dumb. Well played.

Yeah but think about all the laughs shared by programmers (and try not to think of the furrowed brows of the non-programmers)

Ok, I get it now.

[Darren Dirt]

Also, it *appears* "polyglot" which in theory means the output for C is the output for Perl or Python or whatever the other language is -- although it might depend on compilers or whatnot, although now it's clear the intention is to be the same "destination", just gets there via a different "route".

http://en.wikipedia.org/wiki/Polyglot_%28computing%29

[Thorin]

Well, now I know Thorin reads my posts all the way through LOL

Yes I do.  I'm compelled to.  Not fully reading a post feels ... wrong.

What OCD?

Anyway, my first introduction to the word "polyglot" was as a kid when I was reading the OD&D Masters ruleset and they were talking about the different paths to demigodhood.  It feels weird using that word to describe a bunch of text interpreted as code for multiple compilers.

[Mr. Analog]

Funny you mention that I was thinking about the first time I found out that all Palladium RPGs were compatible with each other with some minor tweaking.