enum SystemFacFlag {
    SFF_MINERALS = 1,
    SFF_ORGANICS = 2,
    SFF_RADIOACTIVES = 4
};

for (int f = 0; f <= (SFF_MINERALS | SFF_ORGANICS | SFF_RADIOACTIVES); ++f) {
    // do stuff with f, including indexing an array with it;
    if (f & SFF_MINERALS) { /* more stuff */ }
    if (f & SFF_ORGANICS) { /* still more stuff */ }
    if (f & SFF_RADIOACTIVES) { /* even more stuff */ }
}