I have a custom container class for which I'd like to write the iterator
and const_iterator
classes.
I never did this before and I failed to find an appropriate how-to. What are the guidelines regarding iterator creation, and what should I be aware of ?
I'd also like to avoid code duplication (I feel that const_iterator
and iterator
share many things; should one subclass the other ?).
Foot note: I'm pretty sure Boost has something to ease this but I can't use it here, for many stupid reasons.
std::iterator
with random_access_iterator_tag
.These base classes define all type definitions required by STL and do other work.To avoid code duplication iterator class should be a template class and be parametrized by "value type", "pointer type", "reference type" or all of them (depends on implementation). For example:
// iterator class is parametrized by pointer type
template <typename PointerType> class MyIterator {
// iterator class definition goes here
};
typedef MyIterator<int*> iterator_type;
typedef MyIterator<const int*> const_iterator_type;
Notice iterator_type
and const_iterator_type
type definitions: they are types for your non-const and const iterators.
See Also: standard library reference
EDIT: std::iterator
is deprecated since C++17. See a relating discussion here.