gistfile1.cpp

#import <iostream>

struct Octree {
  Octree() : index(created++){}
  void print_index()
  {
    std::cout << "print_index() " << index << std::endl;
  }
  int index;
  static int created;
};

int Octree::created = 0;

namespace detail
{
  const unsigned int X_BIT = 1 << 0;
  const unsigned int Y_BIT = 1 << 1;
  const unsigned int Z_BIT = 1 << 2;
}

struct Nodes{
  Octree subtree[8];
  Octree& operator()(bool x, bool y, bool z)
  {
    return subtree
      [
       (x ? detail::X_BIT : 0) |
       (y ? detail::Y_BIT : 0) |
       (z ? detail::Z_BIT : 0)
       ];
  }
};

int main()
{
  Nodes nodes;

  nodes(false, false, false).print_index();
  nodes(false, false, true).print_index();
  nodes(true, true, true).print_index();

  return 0;
}

Dantes:test rowanj$ clang++ -o octree octree.cpp && ./octree
print_index() 0
print_index() 4
print_index() 7
Dantes:test rowanj$