#ifndef SINGLETON_H
#define SINGLETON_H

#include <iostream>

template<typename T>
class Singleton
{
public:
    static T* getInstance() noexcept(std::is_nothrow_constructible<T>::value)
    {
        static T instance{token()};
        return &instance;
    }
    virtual ~Singleton() =default;
    Singleton(const Singleton&)=delete;
    Singleton& operator =(const Singleton&)=delete;

protected:
    struct token{}; // helper class
    Singleton() noexcept=default;
};

#endif // SINGLETON_H