From: Daniel Wallin (dalwan01_at_[hidden])
Date: 2004-07-01 06:22:22
Dan wrote:
> I'm trying to use iter_fold with a vector_c to compute the sum of all of the
> integers in the container.
>
> What I have is:
>
> template<typename Sequence>
> struct sum
> {
> typedef typename mpl::iter_fold<
> Sequence,
> typename mpl::begin<Sequence>::type,
> mpl::plus< mpl::deref<_1>, mpl::deref<_2> >;
> // ^ what should this really be?
> > // what do i put after here?
> };
>
> Which obviously won't work. I don't know how to keep a running total as I
> iterate over the sequence with plus.
I don't know why you are using iter_fold instead of just fold here, but
anyway:
template<typename Sequence>
struct sum
{
typedef typename mpl::iter_fold<
Sequence
, mpl::int_<0>
, mpl::plus<mpl::_1, mpl::deref<mpl::_2> >
>::type type;
};
HTH,
-- Daniel Wallin