std::ranges::all_of, std::ranges::any_of, std::ranges::none_of
Defined in header <algorithm>
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Call signature |
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template< std::input_iterator I, std::sentinel_for<I> S, class Proj = std::identity, |
(1) | (since C++20) |
template< ranges::input_range R, class Proj = std::identity, std::indirect_unary_predicate< |
(2) | (since C++20) |
template< std::input_iterator I, std::sentinel_for<I> S, class Proj = std::identity, |
(3) | (since C++20) |
template< ranges::input_range R, class Proj = std::identity, std::indirect_unary_predicate< |
(4) | (since C++20) |
template< std::input_iterator I, std::sentinel_for<I> S, class Proj = std::identity, |
(5) | (since C++20) |
template< ranges::input_range R, class Proj = std::identity, std::indirect_unary_predicate< |
(6) | (since C++20) |
[
first,
last)
(after projecting with the projection proj).[
first,
last)
(after projecting with the projection proj).[
first,
last)
(after projecting with the projection proj).The function-like entities described on this page are niebloids, that is:
- Explicit template argument lists cannot be specified when calling any of them.
- None of them are visible to argument-dependent lookup.
- When any of them are found by normal unqualified lookup as the name to the left of the function-call operator, argument-dependent lookup is inhibited.
In practice, they may be implemented as function objects, or with special compiler extensions.
Contents |
Parameters
first, last | - | the range of the elements to examine |
r | - | the range of the elements to examine |
pred | - | predicate to apply to the projected elements |
proj | - | projection to apply to the elements |
Return value
i
in the range, false otherwise. Returns true if the range is empty.i
in the range, false otherwise. Returns false if the range is empty.i
in the range, false otherwise. Returns true if the range is empty.See also Notes below.
Complexity
At most last - first applications of the predicate and the projection.
Possible implementation
all_of (1,2) |
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struct all_of_fn { template<std::input_iterator I, std::sentinel_for<I> S, class Proj = std::identity, std::indirect_unary_predicate<std::projected<I, Proj>> Pred> constexpr bool operator()(I first, S last, Pred pred, Proj proj = {}) const { return ranges::find_if_not(first, last, std::ref(pred), std::ref(proj)) == last; } template<ranges::input_range R, class Proj = std::identity, std::indirect_unary_predicate< std::projected<ranges::iterator_t<R>,Proj>> Pred> constexpr bool operator()(R&& r, Pred pred, Proj proj = {}) const { return operator()(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj)); } }; inline constexpr all_of_fn all_of; |
any_of (3,4) |
struct any_of_fn { template<std::input_iterator I, std::sentinel_for<I> S, class Proj = std::identity, std::indirect_unary_predicate<std::projected<I, Proj>> Pred> constexpr bool operator()(I first, S last, Pred pred, Proj proj = {}) const { return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) != last; } template<ranges::input_range R, class Proj = std::identity, std::indirect_unary_predicate< std::projected<ranges::iterator_t<R>,Proj>> Pred> constexpr bool operator()(R&& r, Pred pred, Proj proj = {}) const { return operator()(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj)); } }; inline constexpr any_of_fn any_of; |
none_of (5,6) |
struct none_of_fn { template<std::input_iterator I, std::sentinel_for<I> S, class Proj = std::identity, std::indirect_unary_predicate<std::projected<I, Proj>> Pred> constexpr bool operator()(I first, S last, Pred pred, Proj proj = {}) const { return ranges::find_if(first, last, std::ref(pred), std::ref(proj)) == last; } template<ranges::input_range R, class Proj = std::identity, std::indirect_unary_predicate< std::projected<ranges::iterator_t<R>,Proj>> Pred> constexpr bool operator()(R&& r, Pred pred, Proj proj = {}) const { return operator()(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj)); } }; inline constexpr none_of_fn none_of; |
Notes
The return value represented in the form of the Truth table is:
input range contains | ||||
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all true, none false |
some true, some false |
none true, all false |
none true, none false (empty range) | |
1,2) all_of | true | false | false | true |
3,4) any_of | true | true | false | false |
5,6) none_of | false | false | true | true |
Example
#include <algorithm> #include <functional> #include <iostream> #include <iterator> #include <numeric> #include <vector> namespace ranges = std::ranges; constexpr bool some_of(auto&& r, auto&& pred) // some but not all { return not (ranges::all_of(r, pred) or ranges::none_of(r, pred)); } constexpr auto w = {1, 2, 3}; static_assert(!some_of(w, [](int x) { return x < 1; })); static_assert( some_of(w, [](int x) { return x < 2; })); static_assert(!some_of(w, [](int x) { return x < 4; })); 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, std::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"; auto DivisibleBy = [](int d) { return [d](int m) { return m % 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) |