Checks whether the second range matches the suffix of the first range.

The function-like entities described on this page arealgorithm function objects (informally known asniebloids), that is:

• Explicit template argument lists cannot be specified when calling any of them.
• None of them are visible toargument-dependent lookup.
• When any of them are found bynormal unqualified lookup as the name to the left of the function-call operator,argument-dependent lookup is inhibited.

[edit]Parameters

[edit]Return value

true if the second range matches the suffix of the first range,false otherwise.

[edit]Complexity

Generally linear: at most\(\scriptsize \min(N1,N2) \)min(N1,N2) applications of the predicate and both projections. The predicate and both projections are not applied ifN1< N2 istrue.

If bothN1 andN2 can be calculated in constant time (i.e. both iterator-sentinel type pairs modelsized_sentinel_for, or both range types modelsized_range) andN1< N2 istrue, the time complexity is constant.

[edit]Possible implementation

struct ends_with_fn{template<std::input_iterator I1,std::sentinel_for<I1> S1,std::input_iterator I2,std::sentinel_for<I2> S2,class Pred=ranges::equal_to,class Proj1=std::identity,class Proj2=std::identity>    requires(std::forward_iterator<I1>||std::sized_sentinel_for<S1, I1>)&&(std::forward_iterator<I2>||std::sized_sentinel_for<S2, I2>)&&std::indirectly_comparable<I1, I2, Pred, Proj1, Proj2>constexprbool operator()(I1 first1, S1 last1, I2 first2, S2 last2,                              Pred pred={}, Proj1 proj1={}, Proj2 proj2={})const{constauto n1=ranges::distance(first1, last1);constauto n2=ranges::distance(first2, last2);if(n1< n2)returnfalse;ranges::advance(first1, n1- n2);returnranges::equal(std::move(first1), last1,                             std::move(first2), last2,                             pred, proj1, proj2);} template<ranges::input_range R1,ranges::input_range R2,class Pred=ranges::equal_to,class Proj1=std::identity,class Proj2=std::identity>    requires(ranges::forward_range<R1>||ranges::sized_range<R1>)&&(ranges::forward_range<R2>||ranges::sized_range<R2>)&&std::indirectly_comparable<ranges::iterator_t<R1>,ranges::iterator_t<R2>,                                        Pred, Proj1, Proj2>constexprbool operator()(R1&& r1, R2&& r2,                              Pred pred={}, Proj1 proj1={}, Proj2 proj2={})const{constauto n1=ranges::distance(r1);constauto n2=ranges::distance(r2);if(n1< n2)returnfalse;returnranges::equal(views::drop(ranges::ref_view(r1),                                         n1-static_cast<decltype(n1)>(n2)),                             r2, pred, proj1, proj2);}}; inlineconstexpr ends_with_fn ends_with{};

[edit]Notes

[edit]Example

#include <algorithm>#include <array> static_assert(! std::ranges::ends_with("for","cast")&&    std::ranges::ends_with("dynamic_cast","cast")&&! std::ranges::ends_with("as_const","cast")&&    std::ranges::ends_with("bit_cast","cast")&&! std::ranges::ends_with("to_underlying","cast")&&    std::ranges::ends_with(std::array{1,2,3,4},std::array{3,4})&&! std::ranges::ends_with(std::array{1,2,3,4},std::array{4,5})); int main(){}

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

1. ↑Its result might be of aninteger-class type, in this caseranges::drop_view cannot be constructed.

[edit]See also

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