I am creating a tuple of vectors of various objects – and it is a singleton. I have nested this singleton class within another class.
Right now I have no idea what the issue is, but I am unable to revise and set values to member variables of the objects in the vectors of that singleton tuple (that is a mouthful!). Basically, I think I am struggling with the syntax, and it is due to my lack of experience. I have searched for someone else doing this, but unable to grasp what might be taking place.

The crux of the issue is with size_t addDevice(); below:

#include <string>
#include <vector>
#include <tuple>

#define TOTAL 100

typedef std::tuple<
    std::vector<X>,
    std::vector<Y>,
    std::vector<Z>
> SingletonTuple;

class Device
{
public:
   Device() { activeStatus = false; };
private:
   bool activeStatus;
};

class Controller
{    
public:
    Controller() {  };
    size_t addDevice();
    class Singleton
    {
    public:
        static Singleton& Instance()
        {
            static Singleton singleton(TOTAL);
            return singleton;
        }
    private:
        friend class Controller;
        size_t numDevices;
        SingletoneTuple singletonTuple;
        Singleton(size_t total);
    };
};

Controller::Singleton::Singleton(size_t total)
{
    numDevices = total;
    Singleton::singleton = std::make_tuple(std::vector<X>(total), std::vector<Y>(total), std::vector<Z>(total));
}

size_t Controller::addDevice()
{
    index = computeIndex(); //defined elsewhere but assume it returns an index
    std::get<std::vector<X>>(singleton)[index].activeStatus = true;
    std::get<std::vector<Y>>(singleton)[index].activeStatus = true;
    std::get<std::vector<Z>>(singleton)[index].activeStatus = true;
    return index;
}

These from above show up as an invalid function regarding std::get:

    std::get<std::vector<X>>(singleton)[index].activeStatus = true;
    std::get<std::vector<Y>>(singleton)[index].activeStatus = true;
    std::get<std::vector<Z>>(singleton)[index].activeStatus = true;

Does anybody know how I should revise the syntax of the above 3 items in regards to having a nested singleton and trying to reference member variables inside objects inside vectors inside a singleton tuple?

I have searched for solutions but it seems nobody is trying this particular approach.