std::set
Defined in header
<set>
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||
template<
class Key, |
(1) | |
namespace pmr {
template <class Key, class Compare = std::less<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
.
Contents |
[edit] Member types
Member type | Definition | ||||
key_type
|
Key
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value_type
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Key
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size_type
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Unsigned integral type (usually std::size_t) | ||||
difference_type
|
Signed integer type (usually std::ptrdiff_t) | ||||
key_compare
|
Compare
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value_compare
|
Compare
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allocator_type
|
Allocator
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reference
|
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const_reference
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pointer
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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> |
[edit] Member functions
constructs the set (public member function) |
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destructs the set (public member function) |
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assigns values to the container (public member function) |
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returns the associated allocator (public member function) |
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Iterators |
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returns an iterator to the beginning (public member function) |
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returns an iterator to the end (public member function) |
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returns a reverse iterator to the beginning (public member function) |
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returns a reverse iterator to the end (public member function) |
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Capacity |
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checks whether the container is empty (public member function) |
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returns the number of elements (public member function) |
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returns the maximum possible number of elements (public member function) |
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Modifiers |
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clears the contents (public member function) |
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inserts elements (public member function) |
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(C++11)
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constructs element in-place (public member function) |
(C++11)
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constructs elements in-place using a hint (public member function) |
erases elements (public member function) |
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swaps the contents (public member function) |
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Lookup |
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returns the number of elements matching specific key (public member function) |
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finds element with specific key (public member function) |
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returns range of elements matching a specific key (public member function) |
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returns an iterator to the first element not less than the given key (public member function) |
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returns an iterator to the first element greater than the given key (public member function) |
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Observers |
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returns the function that compares keys (public member function) |
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returns the function that compares keys in objects of type value_type (public member function) |
[edit] Non-member functions
lexicographically compares the values in the set (function template) |
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specializes the std::swap algorithm (function template) |
[edit] Notes
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.