Calculation before compile using template

main.cpp

#include <iostream>
#include <vector>

using std::size_t;

template<size_t index>
struct factorial
{
  const static size_t value = index * factorial<index-1>::value;
};

template<>
struct factorial<0>
{
  const static size_t value = 1;
};

template<size_t index>
struct napier
{
  const static double value = napier<index-1>::value + 1.0 / factorial<index>::value;
};

template<>
struct napier<0>
{
  const static double value = 1.0 / factorial<0>::value;
};


template<size_t index>
struct power
{
  // const static double value = power<index-1>::value * 10;
  const static double value = power<index >> 1 >::value * power<index >> 1 >::value * power<index & 1 >::value;

};

template<>
struct power<1>
{
  const static double value = 10;
};

template<>
struct power<0>
{
  const static double value = 1;
};



int main()
{
  std::cerr.precision(17);
  std::cerr << power<5>::value << std::endl;

  return 0;
}