#include <iostream>

template <typename T>
std::enable_if_t<std::is_arithmetic<T>::value, T> sq(T x) {
  return x * x;
}

int main() {
  float x = 4.4;

  std::cout << "double: " << sq((double)5.3) << "\nlong: " << sq(4l);

  return 0;
}