[C++] Do std::stack and std::queue poll their elements?

It depends. The stack and queue are container adapters. You have to provide an underlying implementation that will control how memory is used. Give it a vector and it will pool memory. Give it a list and it won't. By default it uses the deque which is somewhere between a list and a vector on memory use. It allocates in pages and releases pages when they aren't necessary any more.

OK, thanks!