Is the C++ Iterator STL a template, class or an interface?

Question

I hear it always being referred to as an interface, but looking at the actual code, it doesn't look like an interface. Why the misnomer if it's not an interface?

Edit below for more clarification. I agree the question wasn't worded the best, but it did bring up a confusing topic. The code in question is from, cplusplus.com/reference/iterator/iterator

template <class Category, class T, class Distance = ptrdiff_t,
          class Pointer = T*, class Reference = T&>
  struct iterator {
    typedef T         value_type;
    typedef Distance  difference_type;
    typedef Pointer   pointer;
    typedef Reference reference;
    typedef Category  iterator_category;
  };

As well as from reading from this link. bogotobogo.com/cplusplus/stl3_iterators.php I hear this from coworkers, classmates, and even some teachers. Verbage such as this, ""The major advantage of iterators is that they offer common interfaces for any container type." The way "interface" is used here in relation to iterators.

A user pointed out below that the term interface is generically used and isn't always used as you would when writing a C++ interface.

"_I hear it always being referred to as an interface_" Hear to being referred as an interface, by whom? I, for instance, don't remember hearing it being called an interface. — Algirdas Preidžius, Sep 14 '18 at 13:41
I should clarify. Here is what I am referring to. http://www.cplusplus.com/reference/iterator/iterator/ — jaxkewl, Sep 14 '18 at 13:43
this could make a not so bad question if there wasnt strange premises and if you told us where you got this idea from / what code you are talking about — 463035818_is_not_an_ai, Sep 14 '18 at 13:43
And here as well, https://www.bogotobogo.com/cplusplus/stl3_iterators.php. Verbage such as this, "The major advantage of iterators is that they offer common interfaces for any container type. " from the link I posted. — jaxkewl, Sep 14 '18 at 13:44
@jaxkewl That reference is not a good resource. Consider switching to cppreference.com. — Algirdas Preidžius, Sep 14 '18 at 13:44
the meaning of "interface" is rather wide. One could also say that `std::vector` offers a convinient interface to a dynamic array, but that doesnt make `std::vector` an interface in the sense of declaring only abstract methods, if thats your misunderstanding — 463035818_is_not_an_ai, Sep 14 '18 at 13:50
I think @user463035818's response has been the most helpful. — jaxkewl, Sep 14 '18 at 13:52
you should maybe edit your question to include all the information from your comments — 463035818_is_not_an_ai, Sep 14 '18 at 14:01

score 3 · Accepted Answer · answered Sep 14 '18 at 13:54

3

It's none of those.

It's actually a concept.

Concepts are becoming increasingly important in C++ and you should try to become familiar with them. See https://en.cppreference.com/w/cpp/language/constraints

answered Sep 14 '18 at 13:54

Bathsheba

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as I understand concepts have been present in c++ since long time and its high time that they are put on some solid formal ground – 463035818_is_not_an_ai Sep 14 '18 at 13:59
@user463035818: Absolutely! – Bathsheba Sep 14 '18 at 13:59
It should be noted, though, that the term `concept` has been having a meaning in C++ for many years, but C++20 is going to change it from an meta-specification to an actual language feature. – lisyarus Sep 14 '18 at 14:00
A "concept" in that sense is just a particular kind of interface. – Cubic Sep 14 '18 at 14:38

Is the C++ Iterator STL a template, class or an interface?

1 Answers1