maxdefaultdeclval.hpp

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 <utility>

template<typename T1, typename T2,
         typename RT = std::decay_t<decltype(true ? std::declval<T1>()
                                                  : std::declval<T2>())>>
RT max (T1 a, T2 b)
{
  return  b < a ? a : b;
}