I'm wondering what the benefits of using rbegin() rather than end() - 1 are for STL containers.
For example, why would you use something like:
vector<int> v;
v.push_back(999);
vector<int>::reverse_iterator r = v.rbegin();
vector<int>::iterator i = r.base();
Rather than:
vector<int> v;
v.push_back(999);
auto r = v.end() - 1;
rbegin()
return an iterator with a reverseoperator++
; that is, with areverse_iterator
you can iterate through a container going backward.Example:
Furthermore, some standard containers like
std::forward_list
, return forward iterators, so you wouldn't be able to dol.end()-1
.Finally, if you have to pass your iterator to some algorithm like
std::for_each
that presuppose the use of theoperator++
, you are forced to use areverse_iterator
.If the container is empty,
end() - 1
will not be defined.