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
template<typename DstT, typename SrcT>
DstT implicit_cast (SrcT const& x) // SrcT can be deduced, but DstT cannot
{
return x;
}
int main()
{
double value = implicit_cast<double>(-1);
}