Honestly, the best way to find that is to Google it ... or DuckDuckGo. Search for
c++ "pure virtual function".
There's an entire site devoted to programmer interview questions. The answer to this one is at
http://www.programmerinterview.com/i...tual-function/.
And, as you'll quickly see from actually reading that page ... you'll quickly see that the C++ implementation of that idea is rather hosed-up. A function is shown as "assigned the value of zero," without explanation. This is to indicate that the function "has no body or definition," except, as the author goes on to say, it actually
can. Other languages (and implementations of C++) deal with that problem by formally introducing the keyword,
abstract. (See also
http://www.programmerinterview.com/i...tract-keyword/.)
And, with all that said, I shan't go
[much...] into a discussion here of what I think about "programmer interviews." I think that you can readily guess what I would say.
Anytime I taught a programming class in community college, I would let the students bring a "cheat sheet." One 8-1/2x11" piece of paper, filled on both sides with whatever they wanted, provided only if it was done by them. (They'd staple their sheets to the tests when they turned them in.) One enterprising student condensed 8 pages' worth of material and brought a magnifying glass with him ... which certainly attracted my interest, as did my observation that he
never looked at it during the entire test, for which he received an "A."
I don't need to know if a programmer candidate has memorized the never-read pages of a programming language user-manual. I need to know if he/she has good social skills, can work well with others as a team, can delve into
existing piles of execrable stinking crap legacy source-code, and can "think like a programmer." For the rest of it, I've got plenty of well-thumbed books on the shelf.