Re: Last element in a container
<pr2345@gmail.com> wrote:
Hi,
I want to get an iterator pointing to the last element of a container,
where the container is any of the standard containers (vector, list,
set, map, etc). For example:
typedef std::set<int> Container;
typedef Container::iterator Iter;
Iter last_element(Container & c)
{
if (c.empty())
return c.end();
Iter it = c.end();
return --it;
}
Is this guaranteed to work? Is it legal to decrement the end iterator
of a container (provided the container is non-empty), and will that
always give the last element?
This requires member functions empty() and end() which I believe all
STL containers have, All the provided containers in the lib as per c++98
are bidirectional but the iterators of additional containers from tr1
are only required to have forward iterators.
you require
1) empty() - ok
2) end() - ok
3 iterator::operator --(). not guaranteed for unsorted_* containers.
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