what is the toughest C code u have written ??

a company named VMware ..came to our campus on 3rd .. initially their package was nice enough and their profile was a software developer .. so i was interested in working with this company .. and their niche area .. the kind of work they do is amazing .. as they shown in their placement talk they won every single award in the area for last some four years ..

the recruitment procedure was rigorous .. they had some 115 min of written test ( software c,os and aptitude ) followed by some three to four rounds of interview ..

i was lucky enough to get through first round ( after some 5 to 6 months i cleared a written test , the one which i cleared in that i eventually got through ) so was excited abt the interview ..

the biggest hurdle was PROJECT !! they were giving more emphasis on project done throughout your ug degree .. they wanted people that has done some kernel code modification like stuff .. and my projects were .. one is effect of parasitic capacitance on a MEMS sensor .. and we did all kind of simulation .. and other projects are we made a Lock Pulley for a nearby village .. so that was it ..

my interview was abt to start at 10 30 am on next day .. read some stuff abt os in the morning ... went for the interview in tp .. found out there that they were calling people in the random order .. so waited chatting outside .. was very hot outside so after some time i removed my tie , folded my sleeves ..

after long wait eventually my interview started at 12 .. just went inside .. there was only one guy taking the interview .. he was looking at my cv ... he just started by asking about Instrumentation engg .. i gave him loads of fundae that it is a interdisciplinary course wherein we study many facets of engg such as instrumentation ( ie sensors ) , electronics , control engg and computer science ..

after that he just started to ask me abt some simple question on os .. which i confidently answered all of them .. after that he started to ask me abt my projects .. and then i thought i am caught here .. i tried to told him some shit abt MEMS project and didnt seem to be that interseted in it .. so he asked me that what is the toughest C code u written ?

told him that i did some code for tree traversal .. linked list .. i couldnt imagine what might be the toughest code which i have written ( as a matter of fact i havent written any code for last 2 year except for Hello World !! ) ..

at end interviewer told me excellent talking to u .. gve me one pen and one registration license .. and i was very sure what he means by "excellent " ..