avoid auto in type or non type parameters ?

In Templates/intro, I think this may be confusing for beginners :

template<class TypeT, std::size_t Nelts>
MyArray<TypeT, Nelts>::MyArray(TypeT initial_value)
{
    for (auto i = 0ul; i < Nelts; ++i)
        content_[i] = initial_value;
}

as it suggest that beginners know how auto works, and know that std::size_t is an alias for unsigned long. I would go more for:

template<class TypeT, std::size_t Nelts>
MyArray<TypeT, Nelts>::MyArray(TypeT initial_value)
{
    for (std::size_t i = 0; i < Nelts; ++i)
        content_[i] = initial_value;
}