Solving design involving multiple inheritance and composite classes in c++

Question

I have struggled with this design problem for some time. I will do my best to explain what I am trying to do and the various approached that I have seen, what I am trying and wh

Answer 1

I think you have to have one class Galaxy, one class SolarSystem, etc. And yours GalaxyOne, GalaxyTwo SolarSystemOne, SolarSystemTwo etc. are only different objects instantited from these classes.

class SolarSystem { /* … */ };
class Planet{ /* … */ };
class Moon{ /* … */ };

class Galaxy{ /* … */
 public: // Galaxy(...?...){for (...) {read data??; solarSystem.push_back(createSolarSystem(data)); }
 void AddSolarSystem(SolarSystem* ss){solarSystem.push_back(ss);}
 protected:
   std::vector solarSystems;
   /* … */
};

....

Galaxy GalaxyOne, GalaxyTwo;

If we have no way to use this simple aproach... Lets see yours:

class GalaxyOneTwo: public GalaxyOne, 
                    public GalaxyTwo, 
                    public PrimitiveGalaxy{
    /* … */
 using PrimitiveGalaxy::solarSystems;
 GalaxyOneTwo(){solarSystems.reserve(10);}
};

Here you have three private vectors: (using using you make it direct accesible)

std::vector GalaxyOne::solarSystems;
std::vector GalaxyTwo::solarSystems;
std::vector solarSystems; //GalaxyOneTwo::solarSystems;

Is this what you need? Make it protected?