What functions must I implement to make a class iterable? [duplicate]

Answer 1

If your container implements begin() and end() as member functions, and the return type of the functions supports the pre-increment operator, you can use it in most contexts. The important ones that I can think of are:

1. range-for. You can use:

   Container c;
   for ( auto& item : c ) { ... }
   

2. Functions that work with iterators. Example:

   Container c;
   Item item;
   std::find(c.begin(), c.end(), item);
   

Making the iterator a sub-class of std::iterator is best way to ensure that it will be compatible with all the standard algorithms. (Thanks @Adrian).