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std::ranges::is_sorted(3) C++ Standard Libary std::ranges::is_sorted(3) NAME std::ranges::is_sorted - std::ranges::is_sorted Synopsis Defined in header <algorithm> Call signature template< std::forward_iterator I, std::sentinel_for<I> S, class Proj = std::identity, std::indirect_strict_weak_order<std::projected<I, Proj>> Comp = (1) (since ranges::less > C++20) constexpr bool is_sorted( I first, S last, Comp comp = {}, Proj proj = {} ); template< ranges::forward_range R, class Proj = std::identity, std::indirect_strict_weak_order< (2) (since std::projected<ranges::iterator_t<R>, Proj>> Comp = ranges::less > C++20) constexpr bool is_sorted( R&& r, Comp comp = {}, Proj proj = {} ); Checks if the elements in range [first, last) are sorted in non-de- scending order. A sequence is sorted with respect to a comparator comp if for any iterator it pointing to the sequence and any non-negative integer n such that it + n is a valid iterator pointing to an element of the sequence, std::invoke(comp, std::invoke(proj, *(it + n)), std::invoke(proj, *it)) evaluates to false. 1) Elements are compared using the given binary comparison function comp. 2) Same as (1), but uses r as the source range, as if using ranges::begin(r) as first and ranges::end(r) as last. The function-like entities described on this page are niebloids, that is: * Explicit template argument lists may not be specified when call- ing any of them. * None of them is visible to argument-dependent lookup. * When one of them is found by normal unqualified lookup for the name to the left of the function-call operator, it inhibits argument-dependent lookup. In practice, they may be implemented as function objects, or with special compiler extensions. Parameters first, last - iterator-sentinel defining the range to check if it is sorted r - the range to check if it is sorted comp - comparison function to apply to the projected elements proj - projection to apply to the elements Return value true if the elements in the range are sorted according to comp. Complexity Linear in the distance between first and last. Possible implementation struct is_sorted_fn { template<std::forward_iterator I, std::sentinel_for<I> S, class Proj = std::identity, std::indirect_strict_weak_order<std::projected<I, Proj>> Comp = ranges::less> constexpr bool operator()(I first, S last, Comp comp = {}, Proj proj = {}) const { return ranges::is_sorted_until(first, last, comp, proj) == last; } template<ranges::forward_range R, class Proj = std::identity, std::indirect_strict_weak_order< std::projected<ranges::iterator_t<R>, Proj>> Comp = ranges::less> constexpr bool operator()(R&& r, Comp comp = {}, Proj proj = {}) const { return (*this)(ranges::begin(r), ranges::end(r), std::ref(comp), std::ref(proj)); } }; inline constexpr is_sorted_fn is_sorted; Notes ranges::is_sorted returns true for empty ranges and ranges of length one. Example // Run this code #include <algorithm> #include <iostream> #include <iterator> int main() { namespace ranges = std::ranges; std::array digits {3, 1, 4, 1, 5}; ranges::copy(digits, std::ostream_iterator<int>(std::cout, " ")); std::cout << ": is_sorted: " << std::boolalpha << ranges::is_sorted(digits) << '\n'; ranges::sort(digits); ranges::copy(digits, std::ostream_iterator<int>(std::cout, " ")); std::cout << ": is_sorted: " << ranges::is_sorted(ranges::begin(digits), ranges::end(digits)) << '\n'; } Output: 3 1 4 1 5 : is_sorted: false 1 1 3 4 5 : is_sorted: true See also ranges::is_sorted_until finds the largest sorted subrange (C++20) (niebloid) is_sorted checks whether a range is sorted into as- cending order (C++11) (function template) http://cppreference.com 2022.07.31 std::ranges::is_sorted(3)
NAME | Synopsis | Parameters | Return value | Complexity | Possible implementation | Notes | Example | Output: | See also
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