Dynamically sized non resizable array [duplicate]

Question

Is there a C++ type that acts like a "dynamically sized non resizable array"? This kind of type can be thought of as one of two things:

• vector<T> but without resize, push_back, etc.
• array<T,N> but where N is dynamic and not static.

I do not want a solution that only works if the type of the elements within the array is a non-copyable type. I want a generic solution.

Answer 1

Yes, there (pretty much) is. std::unique_ptr<T[]>. The primary template has a partial specialisation for this case, which provides the appropriate interface (operator [], no operator * etc.)

Alternatively, you can wrap std::vector in your own class and restrict its interface. You could even do that by deriving a class from std::vector using non-public inheritance and publishing only the relevant parts of its interface:

template <class T, class A = std::allocator<T>>
struct FixedVector : private std::vector<T, A>
{
  using FixedVector::vector::vector;
  using FixedVector::vector::operator=;
  using FixedVector::vector::get_allocator;
  using FixedVector::vector::at;
  using FixedVector::vector::front;
  using FixedVector::vector::back;
  using FixedVector::vector::data;
  using FixedVector::vector::begin;
  using FixedVector::vector::cbegin;
  using FixedVector::vector::end;
  using FixedVector::vector::cend;
  using FixedVector::vector::empty;
  using FixedVector::vector::size;
  using FixedVector::vector::operator[];
};