what is this kind of code?

[Dy7SLyTq]

so i found this code a while back and i cant make heads or tails of it.

template <unsigned int exponent>
inline double intpow(double base)
{
  return intpow<exponent-1>(base) * base;
}

template <>
inline double intpow<0>(double base)
{
  return 1;
}

int main()
{
  cout << intpow<12>(1.2345) << " == " << pow(1.2345, 12) << endl;
}

obviously its templates of some kind, but lines 4 and and the second function confuse me

[1yR4jE8b]

It's template meta-programming. I was going to try and explain it myself, but the wikipedia article does a much better job.

https://en.wikipedia.org/wiki/Template_metaprogramming

[Dy7SLyTq]

thanks. i think i understand. so in what cases can this be useful?