one question would be "write some code to sort a std::vector".
You've got to be careful with that.
Telling a programmer candidate to implement a sorting routine is a very common requirement. They may have come from four or five or ten interviews where every single one asked them to implement a sorting routine.
The individual may not catch the nuance in your question that they are allowed to call a sorting routine.
Just because you are feeling like throwing a curveball to the candidate with subtle wording does not mean you should punish them if they don't catch the subtlety.
