// CC0
#include <memory>
#include <vector>

template<class T>
class PtrClass
{
public:
    using Ptr = std::shared_ptr<T>;
    using UPtr = std::unique_ptr<T>;

    template <class...Args>
    static Ptr create(Args... args)
    {
        return std::make_shared<_concrete>(std::forward<Args>(args)...);
    }

    template <class...Args>
    static UPtr createUnique(Args... args)
    {
        return std::make_unique<_concrete>(std::forward<Args>(args)...);
    }

private:
    struct _concrete : public T{};
};

class Something : public PtrClass<Something>
{
protected:
    Something();
};

void foo()
{
    auto s = Something::create();
    auto us = Something::createUnique();
    // auto s2 = new Something;// error
    // Something s3; // error
}