The following code example is taken from the book
C++ Templates - The Complete Guide, 2nd Edition
by David Vandevoorde, Nicolai M. Josuttis, and Douglas Gregor,
Addison-Wesley, 2017
© Copyright David Vandevoorde, Nicolai M. Josuttis, Douglas Gregor 2017
#include <cstddef>
template<typename T>
struct IsArrayT : std::false_type { // primary template: not an array
};
template<typename T, std::size_t N>
struct IsArrayT<T[N]> : std::true_type { // partial specialization for arrays
using BaseT = T;
static constexpr std::size_t size = N;
};
template<typename T>
struct IsArrayT<T[]> : std::true_type { // partial specialization for unbound arrays
using BaseT = T;
static constexpr std::size_t size = 0;
};