Question

I read that The ADT stack can be implemented using

An array

A linked list

The ADT list

But when I’m using the stack I just call stack library. Which of these implementation stack library use?

Answer 1

std::stack is a container adapter that uses some other container as the underlying storage for the data. That defaults to std::deque, but you can specify another sequence such as std::list or std::vector if you prefer.

The requirements on the underlying container are pretty minimal — if memory serves, it needs to support a back(), push_back(), pop_back(), size() and swap() (and the last two aren’t really needed unless you use stack::size() or stack::swap(), which probably aren’t all that common).