Dr Herbie wrote:
"What is polymorphism and why is is useful?"

I was shocked at the number of candidates that couldn't separate polymorphism from class inheritance and I don't think I've met one yet who could explain why it was useful (other than inheriting functionality, which is not the correct answer).

Also, for C#, ask them to explain garbage collection.

good questions, also you may ask when Dispose method is called Smiley