Ayende @ Rahien

Hi!
My name is Oren Eini
Founder of Hibernating Rhinos LTD and RavenDB.
You can reach me by email or phone:

ayende@ayende.com

+972 52-548-6969

, @ Q a b c

Posts: 6,391 | Comments: 47,401

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Jul 02 2013

Spot the bug…

time to read 1 min | 39 words

Do you see it? It took me ages to find it.

aTweet bshare cshare 11 comments

Tags:

bugs

Comments

02 Jul 2013
09:09 AM

Igal Tabachnik

Yay scoping braces!

02 Jul 2013
09:10 AM

Fredrik

Ha ha, it's quite subtle, but so obvious once you spot it.

02 Jul 2013
09:11 AM

Sebastian

I think there is something 'else' missing ;-)

02 Jul 2013
09:15 AM

Ramon Smits

Missing else?

02 Jul 2013
09:26 AM

Sam

LOL, I didn't saw it either

02 Jul 2013
09:46 AM

Marc Brooks

Not to mention the sheer lunacy of mid not being related to target in any discernable way. Ugh.

(oh, yeah, and missing else)

02 Jul 2013
10:00 AM

P.Czatrowski

Apart from missing else, what about arithmetic overflow?

I would change the line: var mid = (left + right + 1) / 2;

to this: var mid = left + (right - left + 1) / 2;

You still get the same result, but it's a little bit safer for higher values.

02 Jul 2013
10:08 AM

tobi

The bug aside, I'd use checked((left + right + 1) / 2).

03 Jul 2013
08:25 AM

Roman Boiko

Another potential problem: behavior of comparator might be not aligned with subtraction, so that

_comparator.Compare(mid-1, mid) >=0

05 Jul 2013
07:48 AM

Alex

This is really a tricky problem to spot. :) Everyone is focused on the code inside the brackets and the missing "else" is not being observed very fast.

12 Jul 2013
09:18 AM

Adam Fridental

Sorry to dissapoint, took me a second.

Anyway, I don't belive in scoping braces when they contain 1 line, it's not safer and not easier to read.. just redundant.

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Ayende @ Rahien

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Spot the bug…

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