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Eight, Nine, Ten...

32 replies to this topic

#1Milcho  Members

Posted 18 March 2013 - 10:28 AM

POPULAR

Excerpt from code I recently saw:

#define EIGHT  (0x08)
#define NINE   (0x09)
#define TEN    (0x10)


. . .

I hope I wasn't too subtle - the definition of TEN is what is ... interesting here.

Edited by Milcho, 18 March 2013 - 10:35 AM.

#2Cornstalks  Members

Posted 18 March 2013 - 10:29 AM

POPULAR

Good thing they put parentheses around those literals!

edit:

Oh gosh, I didn't even realize the TEN issue... That's horrible.

Edited by Cornstalks, 18 March 2013 - 10:37 AM.

[ I was ninja'd 71 times before I stopped counting a long time ago ] [ f.k.a. MikeTacular ] [ My Blog ] [ SWFer: Gaplessly looped MP3s in your Flash games ]

#3Milcho  Members

Posted 18 March 2013 - 10:44 AM

edit:
Oh gosh, I didn't even realize the TEN issue... That's horrible.

That edit made my day - that is exactly why this is so scary.

#4bollµ  Members

Posted 18 March 2013 - 11:01 AM

an explanation for the more noobish of us? what's wrong with that definition? >_<;

a WIP 2d game engine: https://code.google.com/p/modulusengine/

English is not my first language, so do feel free to correct me

#5Rattrap  Members

Posted 18 March 2013 - 11:07 AM

an explanation for the more noobish of us? what's wrong with that definition? >_<;

0x10 in 16 in hex.

"I can't believe I'm defending logic to a turing machine." - Kent Woolworth [Other Space]

#6Paradigm Shifter  Members

Posted 18 March 2013 - 11:24 AM

Could be binary coded decimal... and it makes outputting a text value easier as well ;)

Manic Miner on the ZX Spectrum didn't even store the game score or high score in a variable... it just used ASCII text on the screen (the screen area where the score was displayed was never cleared).

The algorithm only added to your score either 1 or 10 or 100 at a time IIRC. It just increased the ASCII value at the screen position by 1 and if that makes it > 9 it made the current digit 0 and added 1 to the next digit along (and looped if that was bumped to > 9 as well).

It then just copied the score to the high score location if the score was larger than the current high score (check was done with another ASCII comparison).

"Most people think, great God will come from the sky, take away everything, and make everybody feel high" - Bob Marley

#7Milcho  Members

Posted 18 March 2013 - 11:53 AM

Could be binary coded decimal... [snip]

That sounds so convoluted it requires its own thread.

Unfortunately that wasn't the case here - this code, according to a colleague who originally fixed it - caused a fatal crash in the software.

#8Tournicoti  Prime Members

Posted 18 March 2013 - 12:55 PM

Obvious, the coder has 8 fingers on each hand

Edited by Tournicoti, 18 March 2013 - 12:57 PM.

#9BGB  Members

Posted 18 March 2013 - 05:39 PM

Obvious, the coder has 8 fingers on each hand

... maybe the use of named constants is what was at fault here ...

...
#define FOURTY_TWO (042)
#define NINETEEN_EIGHTY_FOUR (NINETEEN, EIGHTY, FOUR)
...

#10ApochPiQ  Moderators

Posted 18 March 2013 - 06:16 PM

#define FOURTY_TWO (042)

Eurgh. I have many horror stories of Octal gone awry.
Wielder of the Sacred Wands

#11mhagain  Members

Posted 18 March 2013 - 06:18 PM

#define FOURTY_TWO (042)

That's even worse!!!

It appears that the gentleman thought C++ was extremely difficult and he was overjoyed that the machine was absorbing it; he understood that good C++ is difficult but the best C++ is well-nigh unintelligible.

#12Bacterius  Members

Posted 18 March 2013 - 07:21 PM

That's even worse!!!

This used to happen to me when I was trying to align constants properly. Nowadays I just put spaces instead, been burned too often by this damn octal notation "feature" which I'm guessing nobody actually uses, except the odd raw socket hacker (if even). Permission bits are another one, but constants for those are already defined anyway.

“If I understand the standard right it is legal and safe to do this but the resulting value could be anything.”

#13BGB  Members

Posted 18 March 2013 - 09:36 PM

That's even worse!!!

This used to happen to me when I was trying to align constants properly. Nowadays I just put spaces instead, been burned too often by this damn octal notation "feature" which I'm guessing nobody actually uses, except the odd raw socket hacker (if even). Permission bits are another one, but constants for those are already defined anyway.

at one point I made things more orthogonal (for my script language) by adding several number notations:
0b... //binary
0c... //octal
0d... //decimal
in addition to:
0x... //hexadecimal

then got into a big mental debate as to whether or not to keep '0' by itself as an octal prefix, make it decimal, or maybe just deprecate it and issue a warning...

note, '_' is also a spacer, so:
0d999_999_999
is the same as:
999999999

likewise:
0x5CD13A42_3B9AC9FFL
or:
999_999_999_999_999_999L
or:
0x0DE0_B6B3__A763_FFFFL

#14Sik_the_hedgehog  Members

Posted 18 March 2013 - 09:38 PM

Octal was big back in the day when C was being made, maybe even moreso than hexadecimal. These days nobody really uses it since it can't be aligned nicely to 8-bit (some computers back then had words with a bit count multiple of 3, so octal probably made a lot more of sense).

Don't pay much attention to "the hedgehog" in my nick, it's just because "Sik" was already taken =/ By the way, Sik is pronounced like seek, not like sick.

#15Cornstalks  Members

Posted 18 March 2013 - 09:40 PM

But they could have made it useful by adding pluses!

#define ONE     +1
#define TWENTY  +20
#define HUNDRED +100

// Here's a little example
#include <iostream>

int main()
{
int x = ONE;
std::cout << x << std::endl;

x = ONE HUNDRED;
std::cout << x << std::endl;

x = ONE HUNDRED TWENTY;
std::cout << x << std::endl;

x = ONE HUNDRED TWENTY ONE;
std::cout << x << std::endl;
}


Or even worse:


#define ONE     +0x001
#define TWENTY  +0x020
#define HUNDRED +0x100


Edited by Cornstalks, 18 March 2013 - 09:44 PM.

[ I was ninja'd 71 times before I stopped counting a long time ago ] [ f.k.a. MikeTacular ] [ My Blog ] [ SWFer: Gaplessly looped MP3s in your Flash games ]

#16slicer4ever  GDNet+

Posted 18 March 2013 - 10:02 PM

....snip...

just...just....o god my eyes....

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#17Trienco  Members

Posted 18 March 2013 - 10:23 PM

Still trying to figure out the reasoning behind that. Is that what happens when your code analysis tool complains about "magic numbers" and somebody just decides to "fix it"?

Because having one such tool complain about '0' being a "magic number" really made me question the worth of that tool and what the creators' code would look like.

f@dzhttp://festini.device-zero.de

#18Bacterius  Members

Posted 18 March 2013 - 10:56 PM

But they could have made it useful by adding pluses!

#define ONE     +1
#define TWENTY  +20
#define HUNDRED +100

// Here's a little example
#include <iostream>

int main()
{
int x = ONE;
std::cout << x << std::endl;

x = ONE HUNDRED;
std::cout << x << std::endl;

x = ONE HUNDRED TWENTY;
std::cout << x << std::endl;

x = ONE HUNDRED TWENTY ONE;
std::cout << x << std::endl;
}


Or even worse:


#define ONE     +0x001
#define TWENTY  +0x020
#define HUNDRED +0x100


Sadly this doesn't fully work:

TWO HUNDRED == 102


But don't worry - we can fix it! We just need to be "clever"...

#define AND +0
#define ONE +1
#define TWO +2
#define TWENTY +20
#define HUNDRED *100

// Here's a little example
#include <iostream>

int main()
{
int x = TWO HUNDRED AND TWENTY ONE;
std::cout << x << std::endl;
// prints 221
}

This way you even get to write grammatically correct numbers.

Edited by Bacterius, 18 March 2013 - 11:00 PM.

“If I understand the standard right it is legal and safe to do this but the resulting value could be anything.”

#19Khatharr  Members

Posted 18 March 2013 - 11:07 PM

I think we should pool our efforts and make a programming language where this kind of thing is sane.

void hurrrrrrrr() {__asm sub [ebp+4],5;}

There are ten kinds of people in this world: those who understand binary and those who don't.

#20Hodgman  Moderators

Posted 18 March 2013 - 11:32 PM

I think we should pool our efforts and make a programming language where this kind of thing is sane.

http://thedailywtf.com/Articles/The_Secret_to_Better_C.aspx