std::array<T,N>::back
Min standard notice:
Returns a reference to the last element in the container.
# Declarations
reference back();
(since C++11) (constexpr since C++17)
const_reference back() const;
(since C++11) (constexpr since C++14)
# Return value
Reference to the last element.
# Notes
For a non-empty container c, the expression c.back() is equivalent to *std::prev(c.end()).
# Example
#include <cassert>
#include <array>
int main()
{
std::array<char, 4> letters{'a', 'b', 'c', 'd'};
assert(letters.back() == 'd');
}