#include <iostream>

template <typename T>
class Singleton
{
  public:
    template <typename... Args>
    static T *Instance(Args &&... args)
    {
        if (m_pInstance == nullptr)
            m_pInstance = new T(std::forward<Args>(args)...);
        return m_pInstance;
    }
    static T *GetInstance()
    {
        if (m_pInstance == nullptr)
            throw "theinstanceisnotinit,pleaseinitializetheinstancefirst";
        return m_pInstance;
    }
    static void DestroyInstance()
    {
        delete m_pInstance;
        m_pInstance = nullptr;
    }

  private:
    Singleton(void);
    virtual ~Singleton(void);
    Singleton(const Singleton &);
    Singleton &operator=(const Singleton &);

  private:
    static T *m_pInstance;
};

template <class T>
T *Singleton<T>::m_pInstance = nullptr;

int main()
{
    Singleton<int>::Instance(10);
    int *i = Singleton<int>::GetInstance();
    std::cout << *i << std::endl;
    return 0;
}