std::lexicographical_compare_3way
Defined in header <algorithm> | ||
|---|---|---|
template< class InputIt1, class InputIt2, class Cmp >
constexpr auto lexicographical_compare_3way( InputIt1 first1, InputIt1 last1,
InputIt2 first2, InputIt2 last2,
Cmp comp)
-> std::common_comparison_category_t<decltype(comp(*first1, *first2)), std::strong_ordering>;
| (1) | (since C++20) |
template< class InputIt1, class InputIt2 >
constexpr auto lexicographical_compare_3way( InputIt1 first1, InputIt1 last1,
InputIt2 first2, InputIt2 last2);
| (2) | (since C++20) |
Lexicographically compares two ranges [first1, last1) and [first2, last2) using three-way comparison and produces a result of the strongest applicable comparison category type.
1) Behaves as if defined as follows:
for ( ; first1 != last1 && first2 != last2; void(++first1), void(++first2) )
if (auto cmp = comp(*first1,*first2); cmp != 0)
return cmp;
return first1 != last1 ? std::strong_ordering::greater :
first2 != last2 ? std::strong_ordering::less :
std::strong_ordering::equal;
2) Behaves as if defined as follows:
return std::lexicographical_compare_3way(first1, last1, first2, last2,
[](const auto& t, const auto& u) {
return std::compare_3way(t, u);
});Parameters
| first1, last1 | - | the first range of elements to examine |
| first2, last2 | - | the second range of elements to examine |
| comp | - | a function object type. The behavior is undefined if its return type is not one of the five comparison category types (strong_equality, weak_equality, strong_ordering, weak_ordering, or partial_ordering) |
| Type requirements | ||
-InputIt1, InputIt2 must meet the requirements of LegacyInputIterator. |
||
Return value
A comparison category type as defined above.
Example
See also
|
(C++20) | compares two values using three-way comparison (function template) |
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