std::experimental::ranges::all_of, std::experimental::ranges::any_of, std::experimental::ranges::none_of
From cppreference.com
< cpp | experimental | ranges
Defined in header <experimental/ranges/algorithm>
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template< InputIterator I, Sentinel<I> S, class Proj = ranges::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > |
(1) | (ranges TS) |
template< InputRange Rng, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<Rng>, Proj>> Pred > |
(2) | (ranges TS) |
template< InputIterator I, Sentinel<I> S, class Proj = ranges::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > |
(3) | (ranges TS) |
template< InputRange Rng, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<Rng>, Proj>> Pred > |
(4) | (ranges TS) |
template< InputIterator I, Sentinel<I> S, class Proj = identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > |
(5) | (ranges TS) |
template< InputRange Rng, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<Rng>, Proj>> Pred > |
(6) | (ranges TS) |
1) Checks if unary predicate
pred
returns true for all elements in the range [first, last)
.3) Checks if unary predicate
pred
returns true for at least one element in the range [first, last)
.5) Checks if unary predicate
pred
returns true for no elements in the range [first, last)
.2,4,6) Same as (1,3,5), but uses
rng
as the source range, as if by using ranges::begin(rng)
and ranges::end(rng)
.Parameters
first, last | - | the range of the elements to examine |
rng | - | the range of the elements to examine |
pred | - | predicate to apply to the projected elements |
proj | - | projection to apply to the elements |
Return value
1-2) true if
pred
returns true for all elements in the range, false otherwise. Returns true if the range is empty.3-4) true if
pred
returns true for at least one element in the range, false otherwise. Returns false if the range is empty.5-6) true if
pred
returns true for no elements in the range, false otherwise. Returns true if the range is empty.Complexity
1-6) At most
last - first
applications of the predicate and last - first
applications of the projection.Possible implementation
First version |
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template< InputIterator I, Sentinel<I> S, class Proj = ranges::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > bool all_of( I first, S last, Pred pred, Proj proj = Proj{} ) { return ranges::find_if_not(first, last, std::ref(pred), std::ref(proj)) == last; } template< InputRange Rng, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<Rng>, Proj>> Pred > bool all_of( Rng&& rng, Pred pred, Proj proj = Proj{} ) { return ranges::all_of(ranges::begin(rng), ranges::end(rng), std::ref(pred), std::ref(proj)); } |
Second version |
template< InputIterator I, Sentinel<I> S, class Proj = ranges::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > bool any_of( I first, S last, Pred pred, Proj proj = Proj{} ) { return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) != last; } template< InputRange Rng, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<Rng>, Proj>> Pred > bool any_of( Rng&& rng, Pred pred, Proj proj = Proj{} ) { return ranges::any_of(ranges::begin(rng), ranges::end(rng), std::ref(pred), std::ref(proj)); } |
Third version |
template< InputIterator I, Sentinel<I> S, class Proj = identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > bool none_of( I first, S last, Pred pred, Proj proj = Proj{} ) { return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) == last; } template< InputRange Rng, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<Rng>, Proj>> Pred > bool none_of( Rng&& rng, Pred pred, Proj proj = Proj{} ) { return ranges::none_of(ranges::begin(rng), ranges::end(rng), std::ref(pred), std::ref(proj)); } |
Example
Run this code
#include <vector> #include <numeric> #include <experimental/ranges/algorithm> #include <experimental/ranges/iterator> #include <iterator> #include <iostream> #include <functional> namespace ranges = std::experimental::ranges; int main() { std::vector<int> v(10, 2); std::partial_sum(v.cbegin(), v.cend(), v.begin()); std::cout << "Among the numbers: "; ranges::copy(v, ranges::ostream_iterator<int>(std::cout, " ")); std::cout << '\n'; if (ranges::all_of(v.cbegin(), v.cend(), [](int i){ return i % 2 == 0; })) { std::cout << "All numbers are even\n"; } if (ranges::none_of(v, std::bind(std::modulus<int>(), std::placeholders::_1, 2))) { std::cout << "None of them are odd\n"; } struct DivisibleBy { const int d; DivisibleBy(int n) : d(n) {} bool operator()(int n) const { return n % d == 0; } }; if (ranges::any_of(v, DivisibleBy(7))) { std::cout << "At least one number is divisible by 7\n"; } }
Output:
Among the numbers: 2 4 6 8 10 12 14 16 18 20 All numbers are even None of them are odd At least one number is divisible by 7
See also
(C++11)(C++11)(C++11) |
checks if a predicate is true for all, any or none of the elements in a range (function template) |