| Defined in header
<set> | ||
|---|---|---|
template<
class Key,
class Compare = std::less<Key>,
class Allocator = std::allocator<Key>
> class set;
| (1) | |
namespace pmr {
template <class Key, class Compare = std::less<Key>>
using set = std::set<Key, Compare, std::polymorphic_allocator<Key>>;
}
| (2) | (since C++17) |
std::set is an associative container that contains a sorted set of unique objects of type Key. Sorting is done using the key comparison function Compare. Search, removal, and insertion operations have logarithmic complexity. Sets are usually implemented as red-black trees.
Everywhere the standard library uses the Compare concept, uniqueness is determined by using the equivalence relation. In imprecise terms, two objects a and b are considered equivalent (not unique) if neither compares less than the other: !comp(a, b) && !comp(b, a).
std::set meets the requirements of Container, AllocatorAwareContainer, AssociativeContainer and ReversibleContainer.
| Member type | Definition | ||||
|---|---|---|---|---|---|
key_type | Key |
||||
value_type | Key |
||||
size_type | Unsigned integer type (usually std::size_t) |
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difference_type | Signed integer type (usually std::ptrdiff_t) |
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key_compare | Compare |
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value_compare | Compare |
||||
allocator_type | Allocator |
||||
reference |
|
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const_reference |
|
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pointer |
|
||||
const_pointer |
|
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iterator |
|
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const_iterator | Constant bidirectional iterator | ||||
reverse_iterator | std::reverse_iterator<iterator> |
||||
const_reverse_iterator | std::reverse_iterator<const_iterator> |
||||
node_type | a specialization of node handle representing a container node (since C++17) | ||||
insert_return_type | type describing the result of inserting a node_type in a container of type X with at least three non-static public data members: bool inserted; X::iterator position;, X::node_type node;. This type is MoveConstructible, MoveAssignable, DefaultConstructible, Destructible, and Swappable (since C++17) |
constructs the set (public member function) |
|
destructs the set (public member function) |
|
| assigns values to the container (public member function) |
|
| returns the associated allocator (public member function) |
|
Iterators |
|
| returns an iterator to the beginning (public member function) |
|
| returns an iterator to the end (public member function) |
|
| returns a reverse iterator to the beginning (public member function) |
|
| returns a reverse iterator to the end (public member function) |
|
Capacity |
|
| checks whether the container is empty (public member function) |
|
| returns the number of elements (public member function) |
|
| returns the maximum possible number of elements (public member function) |
|
Modifiers |
|
| clears the contents (public member function) |
|
| inserts elements or nodes (since C++17) (public member function) |
|
| (C++11)
| constructs element in-place (public member function) |
| (C++11)
| constructs elements in-place using a hint (public member function) |
| erases elements (public member function) |
|
| swaps the contents (public member function) |
|
| (C++17)
| extracts nodes from the container (public member function) |
| (C++17)
| splices nodes from another container (public member function) |
Lookup |
|
| returns the number of elements matching specific key (public member function) |
|
| finds element with specific key (public member function) |
|
| returns range of elements matching a specific key (public member function) |
|
| returns an iterator to the first element not less than the given key (public member function) |
|
| returns an iterator to the first element greater than the given key (public member function) |
|
Observers |
|
| returns the function that compares keys (public member function) |
|
| returns the function that compares keys in objects of type value_type (public member function) |
|
| lexicographically compares the values in the set (function template) |
|
specializes the std::swap algorithm (function template) |
The member types iterator and const_iterator may be aliases to the same type. Since iterator is convertible to const_iterator, const_iterator should be used in function parameter lists to avoid violations of the One Definition Rule.
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