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 <iostream>
#include "sqrt1.hpp"
int main()
{
std::cout << "Sqrt<16>::value = " << Sqrt<16>::value << '\n';
std::cout << "Sqrt<25>::value = " << Sqrt<25>::value << '\n';
std::cout << "Sqrt<42>::value = " << Sqrt<42>::value << '\n';
std::cout << "Sqrt<1>::value = " << Sqrt<1>::value << '\n';
}