Does std::stack expose iterators?

Question

Does the std::stack in the C++ STL expose any iterators of the underlying container or should I use that container directly?

Answer 1

The std::stack does expose its underlying container (and therefore iterators) to subclasses through its protected interface. The std::stack's underlying container object corresponds to the (protected) data member c. So if you want to access them, you could extend std::stack a little.

template>
class iterable_stack
: public std::stack
{
    using std::stack::c;

public:

    // expose just the iterators of the underlying container
    auto begin() { return std::begin(c); }
    auto end() { return std::end(c); }

    auto begin() const { return std::begin(c); }
    auto end() const { return std::end(c); }
};

int main()
{
    iterable_stack st;

    st.push(2);
    st.push(5);
    st.push(3);
    st.push(7);
    st.push(9);

    for(auto i: st)
        std::cout << i << ' ';
    std::cout << '\n';
}

Output:

2 5 3 7 9