NAME¶

std::experimental::ranges::for_each - std::experimental::ranges::for_each

Synopsis¶

Defined in header <experimental/ranges/algorithm>
template< InputIterator I, Sentinel<I> S, class Proj =
ranges::identity,

IndirectUnaryInvocable<projected<I, Proj>> Fun > (1) (ranges TS)
ranges::tagged_pair<tag::in(I), tag::fun(Fun)>

for_each(I first, S last, Fun f, Proj proj = Proj{});
template< InputRange R, class Proj = ranges::identity,

IndirectUnaryInvocable<projected<ranges::iterator_t<R>, Proj>> Fun >
ranges::tagged_pair<tag::in(ranges::safe_iterator_t<R>), (2) (ranges TS)
tag::fun(Fun)>

for_each(R&& r, Fun f, Proj proj = Proj{});

1) Invokes the given function object f to the result of invoking the projection proj
on dereferencing every iterator in the range [first, last) (i.e.,ranges::invoke(f,
ranges::invoke(proj, *i))), in order.
2) Same as (1), but uses r as the source range, as if using ranges::begin(r) as
first and ranges::end(r) as last.

For both overloads, if the iterator type is mutable, f may modify the elements of
the range through the dereferenced iterator. If f returns a result, the result is
ignored.

Unlike the rest of the algorithms, for_each is not allowed to make copies of the
elements in the sequence even if they are trivially copyable.

Unlike std::for_each (which requires only MoveConstructible), these functions
require Fun to model CopyConstructible.

Notwithstanding the declarations depicted above, the actual number and order of
template parameters for algorithm declarations is unspecified. Thus, if explicit
template arguments are used when calling an algorithm, the program is probably
non-portable.

Parameters¶

first, last - the range to apply the function to
r - the range to apply the function to
f - callable object to be applied to each projected element in the range
proj - projection to apply to the elements

Return value¶

A tagged_pair object containing the following two members:

* The first member, with the tag tag::in, is the past-the-end iterator of the
source range (that is, an iterator of type I that compares equal to the sentinel
last).
* The second member, with the tag tag::fun, is initialized from std::move(f)
(after all applications of the function object).

Complexity¶

Exactly last - first applications of f and proj

Possible implementation¶

template< InputIterator I, Sentinel<I> S, class Proj = ranges::identity,
IndirectUnaryInvocable<ranges::projected<I, Proj>> Fun >
auto for_each(I first, S last, Fun f, Proj proj = Proj{})
-> ranges::tagged_pair<tag::in(I), tag::fun(Fun)>
{
for(; first != last; ++first) {
ranges::invoke(f, ranges::invoke(proj, *first));
}
return {std::move(first), std::move(f)};
}

Example¶

This section is incomplete
Reason: no example

See also¶

transform applies a function to a range of elements
(function template)
range-for loop(C++11) executes loop over range
for_each applies a function to a range of elements
(function template)
for_each_n applies a function object to the first n elements of a
(C++17) sequence
(function template)