27 Algorithms library [algorithms]

27.8 Sorting and related operations [alg.sorting]

27.8.2 Sorting [alg.sort]

27.8.2.5is_sorted[is.sorted]

```template<class ForwardIterator> constexpr bool is_sorted(ForwardIterator first, ForwardIterator last); ```
Effects: Equivalent to: return is_sorted_until(first, last) == last;
```template<class ExecutionPolicy, class ForwardIterator> bool is_sorted(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator last); ```
Effects: Equivalent to: return is_sorted_until(std::forward<ExecutionPolicy>(exec), first, last) == last;
```template<class ForwardIterator, class Compare> constexpr bool is_sorted(ForwardIterator first, ForwardIterator last, Compare comp); ```
Effects: Equivalent to: return is_sorted_until(first, last, comp) == last;
```template<class ExecutionPolicy, class ForwardIterator, class Compare> bool is_sorted(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator last, Compare comp); ```
Effects: Equivalent to: return is_sorted_until(std::forward<ExecutionPolicy>(exec), first, last, comp) == last;
```template<forward_iterator I, sentinel_for<I> S, class Proj = identity, indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less> constexpr bool ranges::is_sorted(I first, S last, Comp comp = {}, Proj proj = {}); template<forward_range R, class Proj = identity, indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less> constexpr bool ranges::is_sorted(R&& r, Comp comp = {}, Proj proj = {}); ```
Effects: Equivalent to: return ranges​::​is_sorted_until(first, last, comp, proj) == last;
```template<class ForwardIterator> constexpr ForwardIterator is_sorted_until(ForwardIterator first, ForwardIterator last); template<class ExecutionPolicy, class ForwardIterator> ForwardIterator is_sorted_until(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator last); template<class ForwardIterator, class Compare> constexpr ForwardIterator is_sorted_until(ForwardIterator first, ForwardIterator last, Compare comp); template<class ExecutionPolicy, class ForwardIterator, class Compare> ForwardIterator is_sorted_until(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator last, Compare comp); template<forward_iterator I, sentinel_for<I> S, class Proj = identity, indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less> constexpr I ranges::is_sorted_until(I first, S last, Comp comp = {}, Proj proj = {}); template<forward_range R, class Proj = identity, indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less> constexpr borrowed_iterator_t<R> ranges::is_sorted_until(R&& r, Comp comp = {}, Proj proj = {}); ```
Let comp be less{} and proj be identity{} for the overloads with no parameters by those names.
Returns: The last iterator i in [first, last] for which the range [first, i) is sorted with respect to comp and proj.
Complexity: Linear.