I'm aware of the range iterators in boost, and as for this reference, it seems there should be an easy way of doing what I want, but it's not obvious to me.
Say I want to represent a numerical range, 0 to 100 (inclusive or not), say range(0,100)
. I would like to do something like:
for_each(range<int>(0,100).begin(), range<int>(0,100).end(), do_something);
where do_something
is a functor. This iterators shouldn't have the overhead of having an underneath vector or something like this, but to just offer a sequence of integers. Is this possible with the range implementation in boost? Possible at all with normal, standard STL iterators?
boost::counting_iterator
#include <boost/iterator/counting_iterator.hpp>
std::for_each( boost::counting_iterator<int>(0),
boost::counting_iterator<int>(100),
do_something );
Just to add to the other answers if you're coming from a C++11 perspective - if you'd rather use modern for-each loops, you can do this even more cleanly with boost counting_range:
#include <boost/range/counting_range.hpp>
for(auto const &i : boost::counting_range(0, 10)) {
std::cout << i;
}
Outputs:
0123456789
Yes, it is possible. It just seems boost::range doesn't have support for it out of the box, but you can
boost::counting_iterator
, which does just what you wantoperator*()
would return a number, and use that as an iterator for range
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