[nomoresecrets]

When I was interviewing C++ programmers, we had a C++ test, and some stock questions I asked face to face.

However, I found I could pretty much weed the good C++ programmers from the mediocre/just read about C++ before the interview by asking one question:

"What is a virtual function?"

If they have trouble starting to answer it, give them a hint with "What would cause you to type the keyword 'virtual' in your code?"

You would be amazed how many C++ coders don't really know the answer to this, or what is going on (vtables etc, or even just the behaviour).

One candidate answered "I'd make a function virtual if there were any other virtual functions in the class." It seems like there is no shortage of bad answers to this question. All the people who ever gave me a correct answer (hit rate was <10% of candidates) were good C++ developers.

It's a good question :-).