Defined in header <ranges> | ||
|---|---|---|
template<
std::input_or_output_iterator I,
std::sentinel_for<I> S = I,
ranges::subrange_kind K = std::sized_sentinel_for<S, I> ?
ranges::subrange_kind::sized : ranges::subrange_kind::unsized
>
requires (K == ranges::subrange_kind::sized || !std::sized_sentinel_for<S, I>)
class subrange : public ranges::view_interface<subrange<I, S, K>>
| (since C++20) |
The subrange class template combines together an iterator and a sentinel into a single view.
Additionally, the subrange is a sized_range whenever the final template parameter is subrange_kind::sized (which happens when std::sized_sentinel_for<S, I> is satisfied or when size is passed explicitly as a constructor argument). The size record is needed to be stored if and only if std::sized_sentinel_for<S, I> is false and K is subrange_kind::sized.
|
(C++20) | creates a new subrange (public member function) |
|
(C++20) | converts the subrange to a pair-like type (public member function) |
Observers |
|
|
(C++20) | obtains the iterator (public member function) |
|
(C++20) | obtains the sentinel (public member function) |
|
(C++20) | checks whether the subrange is empty (public member function) |
|
(C++20) | obtains the size of the subrange (public member function) |
Iterator operations |
|
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(C++20) | advances the iterator by given distance (public member function) |
|
(C++20) | obtains a copy of the subrange with its iterator decremented by a given distance (public member function) |
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(C++20) | obtains a copy of the subrange with its iterator advanced by a given distance (public member function) |
Inherited from |
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(C++23) | returns a constant iterator to the beginning of the range. (public member function of std::ranges::view_interface<D>) |
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(C++23) | returns a sentinel for the constant iterator of the range. (public member function of std::ranges::view_interface<D>) |
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(C++20) | returns whether the derived view is not empty. Provided if ranges::empty is applicable to it. (public member function of std::ranges::view_interface<D>) |
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(C++20) | gets the address of derived view's data. Provided if its iterator type satisfies contiguous_iterator. (public member function of std::ranges::view_interface<D>) |
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(C++20) | returns the first element in the derived view. Provided if it satisfies forward_range. (public member function of std::ranges::view_interface<D>) |
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(C++20) | returns the last element in the derived view. Provided if it satisfies bidirectional_range and common_range. (public member function of std::ranges::view_interface<D>) |
|
(C++20) | returns the nth element in the derived view. Provided if it satisfies random_access_range. (public member function of std::ranges::view_interface<D>) |
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(C++20) | obtains iterator or sentinel from a std::ranges::subrange (function template) |
|
(C++20) | specifies whether a std::ranges::subrange models std::ranges::sized_range (enum) |
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(C++20) | obtains the number of components of a std::ranges::subrange (class template specialization) |
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(C++20) | obtains the type of the iterator or the sentinel of a std::ranges::subrange (class template specialization) |
template<class I, class S, ranges::subrange_kind K> inline constexpr bool enable_borrowed_range<ranges::subrange<I, S, K>> = true; |
This specialization of std::ranges::enable_borrowed_range makes subrange satisfy borrowed_range.
#include <iostream>
#include <map>
#include <ranges>
#include <string_view>
template<class V>
void mutate(V& v)
{
v += 'A' - 'a';
}
template<class K, class V>
void mutate_map_values(std::multimap<K, V>& m, K k)
{
auto [first, last] = m.equal_range(k);
for (auto& [_, v] : std::ranges::subrange(first, last))
mutate(v);
}
int main()
{
auto print = [](std::string_view rem, auto const& mm)
{
std::cout << rem << "{ ";
for (const auto& [k, v] : mm)
std::cout << "{" << k << ",'" << v << "'} ";
std::cout << "}\n";
};
std::multimap<int, char> mm{ {4,'a'}, {3,'-'}, {4,'b'}, {5,'-'}, {4,'c'} };
print("Before: ", mm);
mutate_map_values(mm, 4);
print("After: ", mm);
}Output:
Before: { {3,'-'} {4,'a'} {4,'b'} {4,'c'} {5,'-'} }
After: { {3,'-'} {4,'A'} {4,'B'} {4,'C'} {5,'-'} }|
(C++20) | helper class template for defining a view, using the curiously recurring template pattern (class template) |
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