std::experimental::ranges::all_of, std::experimental::ranges::any_of, std::experimental::ranges::none_of
来自cppreference.com
< cpp | experimental | ranges
template< InputIterator I, Sentinel<I> S, class Proj = ranges::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > |
(1) | (范围 TS) |
template< InputRange R, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred > |
(2) | (范围 TS) |
template< InputIterator I, Sentinel<I> S, class Proj = ranges::identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > |
(3) | (范围 TS) |
template< InputRange R, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred > |
(4) | (范围 TS) |
template< InputIterator I, Sentinel<I> S, class Proj = identity, IndirectUnaryPredicate<projected<I, Proj>> Pred > |
(5) | (范围 TS) |
template< InputRange R, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred > |
(6) | (范围 TS) |
1) 检查一元谓词 pred 是否对范围
[
first,
last)
中的所有元素返回 true。3) 检查一元谓词 pred 是否对范围
[
first,
last)
中至少一个元素返回 true。5) 检查一元谓词 pred 是否不对范围
[
first,
last)
中任何元素返回 true。参数
first, last | - | 要检验的元素范围 |
rng | - | 要检验的元素范围 |
pred | - | 应用到投影后元素的谓词 |
proj | - | 应用到元素的投影 |
返回值
1,2) 若 pred 对范围中所有元素返回 true 则为 true,否则为 false。若范围为空则返回 true。
3,4) 若 pred 对范围中至少一个元素返回 true 则为 true,否则为 false。若范围为空则返回 false。
5,6) 若 pred 不对范围中任何元素返回 true 则为 true,否则为 false。若范围为空则返回 true。
复杂度
1-6) 至多应用 last - first 次谓词,应用 last - first 次投影。
可能的实现
版本一 |
---|
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 R, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred> bool all_of(R&& r, Pred pred, Proj proj = Proj{}) { return ranges::all_of(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj)); } |
版本二 |
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 R, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred> bool any_of(R&& r, Pred pred, Proj proj = Proj{}) { return ranges::any_of(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj)); } |
版本三 |
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 R, class Proj = ranges::identity, IndirectUnaryPredicate<projected<ranges::iterator_t<R>, Proj>> Pred> bool none_of(R&& r, Pred pred, Proj proj = Proj{}) { return ranges::none_of(ranges::begin(r), ranges::end(r), std::ref(pred), std::ref(proj)); } |
示例
运行此代码
#include <experimental/ranges/algorithm> #include <experimental/ranges/iterator> #include <functional> #include <iostream> #include <iterator> #include <numeric> #include <vector> namespace ranges = std::experimental::ranges; int main() { std::vector<int> v(10, 2); std::partial_sum(v.cbegin(), v.cend(), v.begin()); std::cout << "这些数中: "; 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 << "所有数均为偶数\n"; if (ranges::none_of(v, std::bind(std::modulus<int>(), std::placeholders::_1, 2))) std::cout << "其中没有奇数\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 << "至少一个数可被 7 整除\n"; }
输出:
这些数中: 2 4 6 8 10 12 14 16 18 20 所有数均为偶数 其中没有奇数 至少一个数可被 7 整除
参阅
(C++11)(C++11)(C++11) |
检查谓词是否对范围中所有、任一或无元素为 true (函数模板) |