Planet-> Vector of all Actors
Actor-> Vector of all Behaviors
Behaviour-> Game Logic

class Actor;

class Behaviour
{
  protected:
    Actor* actor;
  public:
    string type;
    Behaviour();
    ~Behaviour();
    virtual void Init(); // virtual because every component needs to override them
    virtual void Tick();
}

// Actor.h
class Planet;

class Actor
{
  private:
    unsigned id;
    string name;
    vector< unique_ptr< Behaviour > > allBehaviours;
  protected:
    Planet* planet;
  public:
    Actor();
    ~Actor();
    void Init(); // Go through all the behaviors and call their Inits and Ticks
    void Tick();

    template <typename T, typename ...Args>
    void AddBehaviour(Args && ...args); // Creates and adds a new Behaviour of type T to the allBehaviours vector

    template <typename T>
    T& GetBehaviour(std::string type); // Loops through all the Behaviours, and returns the Behaviour whose type is the same as type

// Actor.cpp

#include "Planet.h"
#include "Behaviour.h"
#include "Actor.h"

// Implement Functions

// Planet.h

class Actor;

class Planet
{
    private:
      unsigned idCounter = 0;
      string name;
      vector< unique_ptr< Actor > > allActors;
    public:
      unsigned GetNewID();
      void Init();
      void Tick(); // Used to loop through all the Actors

      void AddActor(Actor* newActor); // adds a new Actor to the list of all Actors
      void KillActor(int id); // loops through all the Actors and when it finds an Actor whose unique id is matching the id variable it erases it from the allActors vector

}

// Planet.cpp

#include "Public.h"
#include "Actor.h"
#include "Planet.h"

    Planet::KillActor(int id){
        unsigned i = 0;
        for (auto& a : allActors) {
            if (a->GetID() == id)
                allActors.erase(allActors.begin() + i);
            i++;
        }
    }

    // Other Functions

{
 // other stuff
 win.GetCurrentPlanet()->AddActor(this);
}