A template for binomial coefficients in C++

Here's how you could implement a compile time calculation of
binomial numbers "n over k" in C++ with a template.

#ifndef BINOMIAL_HPP_INCLUDED

#define BINOMIAL_HPP_INCLUDED


template<int n, int k>
struct Binomial
{
  const static int value =  (Binomial<n-1,k-1>::value + Binomial<n-1,k>::value);
};

template<>
struct Binomial<0,0>
{
  const static int value = 1;
};

template<int n>
struct Binomial<n,0>
{
  const static int value = 1;
};

template<int n>
struct Binomial<n,n>
{
  const static int value = 1;
};

template<int n, int k>
inline int binomial()
{
  return Binomial<n,k>::value;
}

#endif

Now let's try it with a short main:

#include "Binomial.hpp"
#include <iostream>

int main()
{
  std::cout << "30 over 15: " << binomial<30,15>() << std::endl;
  return 0;
}
  

30 over 15: 155117520

It works! When it will break depends on your compiler. I used g++ 4.6.2