is_array.cpp

#include <iostream>
#include <cstddef>

template<typename T>
struct IsArray
{
  static constexpr bool value = false;
};

template<typename T>
struct IsArray<T[]>
{
  static constexpr bool value = true;
};

template<typename T, std::size_t N>
struct IsArray<T[N]>
{
  static constexpr bool value = true;
};

class Test;

int main()
{
  std::cout << std::boolalpha
            << IsArray<int>::value << std::endl
            << IsArray<float>::value << std::endl
            << IsArray<Test>::value << std::endl
            << IsArray<int[]>::value << std::endl
            << IsArray<float[]>::value << std::endl
            << IsArray<Test[]>::value << std::endl
            << IsArray<int[21]>::value << std::endl
            << IsArray<float[42]>::value << std::endl
            << IsArray<Test[84]>::value << std::endl
            ;
}