Template metaprogramming calculations

[Hobson]

Hello,

Recently I am trying to learn something new, and I found out that compilation time calculations would be very useful for me quite often. So, I grabbed my copy of google, looked up some sites, and came with this example:

#include <iostream>

template <int N>
struct Fibonacci {
	enum {value = Fibonacci<N-1>::value + Fibonacci<N-2>::value};
};

template <>
struct Fibonacci<1> {
	enum {value = 1};
};

template <>
struct Fibonacci<0> {
	enum {value = 0};
};


int fibonacci(int which) {

	//WHAT GOES HERE?
}

int main() {
	std::cout << "15th Fibonacci number is "<< Fibonacci<15>::value << '\n';

	int which;
	std::cout << "Which Fibonacci number you want to calculate? ";
	std::cin >> which;

	std::cout << which << ". Fibonacci number is " << fibonacci(which) << '\n';
}

Simple as it is, I seem to miss something basic. The thing is, I just do not get how all these precalculated values can help me at runtime. I do not know how to "map" variable value to precalculated template class.
What I do not know yet? What am I doing wrong? Are my expectations that I can somehow "bind" runtime values with ones calculated by metaprogram wrong?

Cheers,
Maciek