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std::ranges::includes(3) C++ Standard Libary std::ranges::includes(3) NAME std::ranges::includes - std::ranges::includes Synopsis Defined in header <algorithm> Call signature template< std::input_iterator I1, std::sentinel_for<I1> S1, std::input_iterator I2, std::sentinel_for<I2> S2, class Proj1 = std::identity, class Proj2 = std::identity, std::indirect_strict_weak_order< (1) (since C++20) std::projected<I1, Proj1>, std::projected<I2, Proj2>> Comp = ranges::less > constexpr bool includes( I1 first1, S1 last1, I2 first2, S2 last2, Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {} ) template< ranges::input_range R1, ranges::input_range R2, class Proj1 = std::identity, class Proj2 = std::identity, std::indirect_strict_weak_order< std::projected<ranges::iterator_t<R1>, Proj1>, (2) (since C++20) std::projected<ranges::iterator_t<R2>, Proj2>> Comp = ranges::less > constexpr bool includes( R1&& r1, R2&& r2, Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {} ) 1) Returns true if the projections of the sorted range [first2, last2) is a subsequence of the projections of the sorted range [first1, last1). 2) Same as (1), but uses r1 and r2 as the source ranges, as if by using ranges::begin(r1) and ranges::begin(r2) as first1 and first2 respec- tively, and ranges::end(r1) and ranges::end(r2) as last1 and last2 respectively. Both ranges must be sorted with the given comparison function comp. A subsequence need not be contiguous. The function-like entities described on this page are niebloids, that is: * Explicit template argument lists cannot be specified when call- ing 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 in- hibited. In practice, they may be implemented as function objects, or with special compiler extensions. Parameters first1, last1 - the sorted range of elements to examine r1 - the sorted range of elements to examine first2, last2 - the sorted range of elements to search for r2 - the sorted range of elements to search for comp - comparison function to apply to the projected ele- ments proj1 - projection to apply to the elements in the first range proj2 - projection to apply to the elements in the second range Return value true if [first2, last2) is a subsequence of [first1, last1); other- wise false. Complexity At most \(\scriptsize 2 \cdot (N_1+N_2-1)\)2(N[1]+N[2]-1) compar- isons, where \(\scriptsize N_1\)N[1] is ranges::distance(r1) and \(\scriptsize N_2\)N[2] is ranges::distance(r2). Possible implementation struct includes_fn { template<std::input_iterator I1, std::sentinel_for<I1> S1, std::input_iterator I2, std::sentinel_for<I2> S2, class Proj1 = std::identity, class Proj2 = std::iden- tity, std::indirect_strict_weak_order< std::projected<I1, Proj1>, std::projected<I2, Proj2>> Comp = ranges::less> constexpr bool operator()(I1 first1, S1 last1, I2 first2, S2 last2, Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {}) const { for (; first2 != last2; ++first1) { if (first1 == last1 || comp(*first2, *first1)) return false; if (!comp(*first1, *first2)) ++first2; } return true; } template<ranges::input_range R1, ranges::input_range R2, class Proj1 = std::identity, class Proj2 = std::iden- tity, std::indirect_strict_weak_order< std::projected<ranges::iterator_t<R1>, Proj1>, std::projected<ranges::iterator_t<R2>, Proj2>> Comp = ranges::less> constexpr bool operator()(R1&& r1, R2&& r2, Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {}) const { return (*this)(ranges::begin(r1), ranges::end(r1), ranges::begin(r2), ranges::end(r2), std::ref(comp), std::ref(proj1), std::ref(proj2)); } }; inline constexpr auto includes = includes_fn {}; Example // Run this code #include <algorithm> #include <cctype> #include <initializer_list> #include <iomanip> #include <iostream> #include <locale> #include <string> template<class T> std::ostream& operator<<(std::ostream& os, std::initializer_list<T> const& list) { for (os << "{ "; auto const& elem : list) os << elem << ' '; return os << "} "; } struct true_false : std::numpunct<char> { std::string do_truename() const { return "? Yes\n"; } std::string do_falsename() const { return "? No\n"; } }; int main() { std::cout.imbue(std::locale(std::cout.getloc(), new true_false)); auto ignore_case = [](char a, char b) { return std::tolower(a) < std::tolower(b); }; const auto a = {'a', 'b', 'c'}, b = {'a', 'c'}, c = {'a', 'a', 'b'}, d = {'g'}, e = {'a', 'c', 'g'}, f = {'A', 'B', 'C'}, z = {'a', 'b', 'c', 'f', 'h', 'x'}; std::cout << z << "includes\n" << std::boolalpha << a << std::ranges::includes(z.begin(), z.end(), a.begin(), a.end()) << b << std::ranges::includes(z, b) << c << std::ranges::includes(z, c) << d << std::ranges::includes(z, d) << e << std::ranges::includes(z, e) << f << std::ranges::includes(z, f, ignore_case); } Output: { a b c f h x } includes { a b c } ? Yes { a c } ? Yes { a a b } ? No { g } ? No { a c g } ? No { A B C } ? Yes See also ranges::set_difference computes the difference between two sets (C++20) (niebloid) ranges::search searches for a range of elements (C++20) (niebloid) ranges::contains ranges::contains_subrange checks if the range contains the given el- ement or subrange (C++23) (niebloid) (C++23) includes returns true if one sequence is a subse- quence of another (function template) http://cppreference.com 2024.06.10 std::ranges::includes(3)
NAME | Synopsis | Parameters | Return value | Complexity | Possible implementation | Example | Output: | See also
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