// Example of use of recursive templates for loop unrolling
template<typename T, int len>
struct AddOp {
  static void add(const T *a, const T *b, T *out)
  {
    AddOp<T,len-1>::add(a,b,out);
    out[len-1] = a[len-1] + b[len-1];
  }
};

// Specialization to act as base case for recursion
template<typename T>
struct AddOp<T,0> {
  static void add(const T *a, const T *b, T *out)
  { }
};