{"id":38,"date":"2006-11-06T08:30:39","date_gmt":"2006-11-06T12:30:39","guid":{"rendered":"http:\/\/www.jrtwine.com\/blog\/?p=38"},"modified":"2008-03-31T17:30:19","modified_gmt":"2008-03-31T21:30:19","slug":"best-wtf-moments-correcting-the-tests-answers","status":"publish","type":"post","link":"https:\/\/jrtwine.com\/blog\/best-wtf-moments-correcting-the-tests-answers\/","title":{"rendered":"Best WTF Moments – Correcting the Test’s Answers"},"content":{"rendered":"

In talking with a friend I was reminded of one of my favorite WTF moments – correcting the answers on an interviewer’s tech questions. Once, while taking an interview for a position, the interviewer was going over my answers for the tech questions and happened to mention that one (or two?) of them were incorrect.<\/p>\n

When I asked about them it turns out to have been questions regarding the size of C++ objects that have no data members. For example:<\/p>\n

\n
class CEmpty { };<\/strong><\/pre>\n
class CEmpty2 { <\/strong>public:  void MyFunc( void ) <\/strong>{ <\/strong>return; <\/strong>} }; <\/strong><\/pre>\n
class CEmpty3 { <\/strong>public: virtual void MyFunc( void ) <\/strong>{ <\/strong>return; <\/strong>} };<\/strong><\/pre>\n<\/blockquote>\n
So what is the size of CEmpty<\/strong>, CEmpty2<\/strong> and CEmpty3<\/strong>?  My answer was that it was basically implementation defined.  The interviewer’s answers said that CEmpty<\/strong> and CEmpty2<\/strong> had a size of zero, and that CEmpty3<\/strong> had a non-zero size. <\/p>\n
I had answered that CEmpty<\/strong> and CEmpty2<\/strong> will have a implementation-specific\/defined size (IME, a size of 1<\/strong>) and that CEmpty3<\/strong> will have a size due to the vtbl<\/strong> that will be added to the class, and added that the size of the vtbl<\/strong> will not<\/strong><\/em> be added to the implementation-specific\/defined size given to otherwise empty objects.  (In other words, if the size of the vtbl<\/strong> pointer is 4 bytes, the object size will be 4, not 5.)<\/p>\n
The interviewer, being a\/the senior developer that I would have been working with or for, did not agree and we ended up with some code snippets being compiled and executed in the VC++ 6.0 IDE.  Wanna take a guess who was correct?<\/p>\n
It turns out that the company’s CTO decided not to accept me for the position.  I was never told why (I otherwise aced the interview, of course), but I was told that the CTO created the interview questions (and answers).  Go figure…!<\/p>\n","protected":false},"excerpt":{"rendered":"
In talking with a friend I was reminded of one of my favorite WTF moments – correcting the answers on an interviewer’s tech questions. Once, while taking an interview for a position, the interviewer was going over my answers for the tech questions and happened to mention that one (or two?) of them were incorrect. […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-38","post","type-post","status-publish","format-standard","hentry","category-developing"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t