ranges_is_sorted.md

is_sorted

• algorithm[meta header]
• std::ranges[meta namespace]
• function template[meta id-type]
• cpp20[meta cpp]

namespace std::ranges {
  template <forward_iterator I,
            sentinel_for<I> S,
            class Proj = identity,
            indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
  constexpr bool
    is_sorted(I first,
              S last,
              Comp comp = {},
              Proj proj = {}); // (1) C++20

  template <forward_range R,
            class Proj = identity,
            indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
  constexpr bool
    is_sorted(R&& r,
              Comp comp = {},
              Proj proj = {}); // (2) C++20
}

• forward_iterator[link /reference/iterator/forward_iterator.md]
• sentinel_for[link /reference/iterator/sentinel_for.md]
• ranges::less[link /reference/functional/ranges_less.md]
• identity[link /reference/functional/identity.md]
• indirect_strict_weak_order[link /reference/iterator/indirect_strict_weak_order.md]
• projected[link /reference/iterator/projected.md]
• forward_range[link /reference/ranges/forward_range.md]
• iterator_t[link /reference/ranges/iterator_t.md]

概要

与えられた範囲がソート済みか判定する。

• (1): イテレータ範囲を指定する
• (2): Rangeを直接指定する

戻り値

• (1) : ranges::is_sorted_until(first, last, comp, proj) == last
• (2) : ranges::is_sorted_until(r, comp, proj) == last

例

#include <iostream>
#include <vector>
#include <algorithm>

int main()
{
  std::vector<int> v = {3, 1, 4, 2, 5};

  std::cout << std::boolalpha;
  std::cout << "before: is sorted? " << std::ranges::is_sorted(v) << std::endl;

  std::ranges::sort(v);

  std::cout << " after: is sorted? " << std::ranges::is_sorted(v) << std::endl;
}

• std::ranges::sort[link ranges_sort.md]
• std::ranges::is_sorted[color ff0000]

出力

before: is sorted? false
 after: is sorted? true

バージョン

言語

• C++20

処理系

• Clang: ??
• GCC: 10.1.0 [mark verified]
• ICC: ??
• Visual C++: 2019 Update 10 [mark verified]

参照

• N4861 25 Algorithms library