double value template

pow_i.cpp

#include <iostream>

using std::size_t;

template<typename _base, size_t _index>
class pow_i
{
public:
  const static double value = pow_i<_base, _index-1 >::value * _base::value; 
};

template<typename _base>
class pow_i<_base, 0>
{
public:
  const static double value = 1;
};

class ten
{
public:
  const static double value = 10;
};

int main()
{
  std::cout << pow_i<ten, 5>::value << std::endl;
  return 0;
};