How to create a std::array wrapper class

Question

Background:

I'm trying to create a few of my own wrapper classes for the STL containers so I can separate implementation from my code base. I have already done alittle bit with my Vector class wrapper like so:

Vector.h

template<typename type>
    class Vector
    {
    public:
        Vector();
        Vector(std::initializer_list<type> initializer);
        Vector(int size, int defaultValue);
        Vector(int size);
        ~Vector();

        void PushBack(type itemToPushBack);
        type AtPosition(int position);

    private:
        std::vector<type> m_collectionOfItems;
    };

As you can see, I have constructors setup and I've used std::vector as a member so that I can just call std::vector functions within my own Vector classes.

Issue:

With std::array I have to specificy a size immediately when instantiating any object. So if I created a member variable like I did with my vector class, I would have to give that array object a size. I would rather the size be specified by the user using some similar constructor setup to Vector's (ex. MyArrayClass myArray(10) ). How might I try and implement this Array wrapper?

std::array wraps a static array, so its size must be specified at compile-time. A std::vector is an array whose size is determined dynamically at run-time. — Remy Lebeau
– Remy Lebeau, Commented Nov 27, 2016 at 4:42
The whole point of std::array, its chief distinction from std::vector, is that its size is determined at compile time and thus it doesn't require a dynamic memory allocation. If you insist on wrapping std::array, your wrapper should have the same property, otherwise it would largely defeat the point. — Igor Tandetnik
– Igor Tandetnik, Commented Nov 27, 2016 at 4:42
The standard containers are already designed to be as interchangeable as possible. Your time may be better served learning what generic functions are available to make container code transferable between containers. If it's not possible using the current standard library functions, the chances are it's not doable. — Galik
– Galik, Commented Nov 27, 2016 at 5:04
alloca and it's variants are non standard and should be avoided if at all possible but one can wrap it similarly. It's available on most compilers but it is NOT standard C++. — doug
– doug, Commented Nov 27, 2016 at 5:12

Kunal Puri · Accepted Answer · 2018-12-30 08:09:35Z

1

I would rather the size be specified by the user using some similar constructor setup to Vector's (ex. MyArrayClass myArray(10) ). How might I try and implement this Array wrapper?

The purpose of std::array, unlike std::vector, is that the size is specified at compile time. Its underlying structure is a plain vanilla array which needs the size at compile time.

I can think of the following wrapper in case it is useful

template <typename T, std::size_t N>
class Array {
  public:
    // stuff
  private:
    std::array<T, N> array_;
};

edited Dec 30, 2018 at 8:09

Kunal Puri

3,4271 gold badge12 silver badges22 bronze badges

answered Nov 27, 2016 at 4:42

Arun

20.6k12 gold badges54 silver badges61 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How to create a std::array wrapper class

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related