std::experimental::ranges::all_of, std::experimental::ranges::any_of, std::experimental::ranges::none_of
来自cppreference.com
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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{} ); |
(1) | (范围 TS) |
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{} ); |
(2) | (范围 TS) |
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{} ); |
(3) | (范围 TS) |
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{} ); |
(4) | (范围 TS) |
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{} ); |
(5) | (范围 TS) |
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{} ); |
(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。2,4,6) 同 (1,3,5)，但以
r 为源范围，如同以 ranges::begin(rng) 为 first 并以 ranges::end(rng) 为 last。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) |