[rubashov]

You can usually establish that someone can't code inside one minute, which happens surprisingly often. You ask: Explain virtual methods to me. If they have C or C++ on their resume you write a three line function that returns a pointer to a stack variable and ask them to explain what's wrong.

If you feel like you even have to ask these questions your candidate selection process is badly broken, but the same approach scales up to all levels.

[steve8918]

I disagree. These days people just memorize the CareerCup e-book, and know the answers to almost every major question out there. I've had plenty of people who knew what a virtual function is, and not know how to code. People have gamed the interview system, it doesn't work anymore.

[deadmansshoes]

"Explain virtual methods to me" - thereby ignoring anyone who can code in Python or Ruby, or anyone from VB.NET and several other languages where Overridable/Overrides is the terminology used.