在堆栈上使用std :: max_element <int>

Question

How exactly I can get the max_element of a stack ? STL stack doesn't any begin() or end() method that I can get the maximum by follow:

auto max = max_element(c.begin(), c.end());

Answer 1

A std::stack has a restricted interface, which is the whole point of that abstraction. If not then you could just have used eg a std::deque . But you have a number of options:

• You can pop all items. If you desire the original stack back at the end then you can just push them back.

• You can access the underlying container (without using a derived class). It's a protected member. The infamous C++ type system loophole for member pointers is helpful, if you're afraid of casting and formally undefined behavior.

• You can use a custom derived class instead of std::stack directly.

This list is not exhaustive but they are the more natural options.

Ie other approaches are fairly unnatural & construed.