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Difference between revisions of "cpp/container/set"

From cppreference.com
< cpp‎ | container
(P0181R1)
m (new member types)
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{{dsc inc | cpp/container/dsc reverse_iterator | set}}
 
{{dsc inc | cpp/container/dsc reverse_iterator | set}}
 
{{dsc inc | cpp/container/dsc const_reverse_iterator | set}}
 
{{dsc inc | cpp/container/dsc const_reverse_iterator | set}}
 +
{{dsc inc | cpp/container/dsc node_type | set}}
 +
{{dsc inc | cpp/container/dsc insert_return_type | set}}
 
{{dsc end}}
 
{{dsc end}}
  

Revision as of 13:06, 19 July 2016

 
 
 
 
Defined in header <set>
(1)
template<

    class Key,
    class Compare = std::less<Key>,
    class Allocator = std::allocator<Key>

> class set;
(until C++17)
template<

    class Key,
    class Compare = std::default_order_t<Key>,
    class Allocator = std::allocator<Key>

> class set;
(since C++17)
namespace pmr {

    template <class Key, class Compare = std::default_order_t<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 Template:concept. Search, removal, and insertion operations have logarithmic complexity. Sets are usually implemented as red-black trees.

Everywhere the standard library uses the Template:concept 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 Template:concept, Template:concept, Template:concept and Template:concept.

Contents

Member types

Member type Definition
key_type Key[edit]
value_type Key[edit]
size_type Unsigned integer type (usually std::size_t)[edit]
difference_type Signed integer type (usually std::ptrdiff_t)[edit]
key_compare Compare[edit]
value_compare Compare[edit]
allocator_type Allocator[edit]
reference value_type&[edit]
const_reference const value_type&[edit]
pointer

Allocator::pointer

(until C++11)

std::allocator_traits<Allocator>::pointer

(since C++11)
[edit]
const_pointer

Allocator::const_pointer

(until C++11)

std::allocator_traits<Allocator>::const_pointer

(since C++11)
[edit]
iterator Constant LegacyBidirectionalIterator to value_type[edit]
const_iterator LegacyBidirectionalIterator to const value_type[edit]
reverse_iterator std::reverse_iterator<iterator>[edit]
const_reverse_iterator std::reverse_iterator<const_iterator>[edit]
node_type (since C++17) a specialization of node handle representing a container node[edit]
insert_return_type (since C++17) type describing the result of inserting a node_type, a specialization of

template<class Iter, class NodeType>
struct /*unspecified*/
{
    Iter     position;
    bool     inserted;
    NodeType node;
};

instantiated with template arguments iterator and node_type.[edit]


Member functions

constructs the set
(public member function) [edit]
destructs the set
(public member function) [edit]
assigns values to the container
(public member function) [edit]
returns the associated allocator
(public member function) [edit]
Iterators
returns an iterator to the beginning
(public member function) [edit]
(C++11)
returns an iterator to the end
(public member function) [edit]
returns a reverse iterator to the beginning
(public member function) [edit]
(C++11)
returns a reverse iterator to the end
(public member function) [edit]
Capacity
checks whether the container is empty
(public member function) [edit]
returns the number of elements
(public member function) [edit]
returns the maximum possible number of elements
(public member function) [edit]
Modifiers
clears the contents
(public member function) [edit]
inserts elements or nodes(since C++17)
(public member function) [edit]
(C++11)
constructs element in-place
(public member function) [edit]
constructs elements in-place using a hint
(public member function) [edit]
erases elements
(public member function) [edit]
swaps the contents
(public member function) [edit]
Lookup
returns the number of elements matching specific key
(public member function) [edit]
finds element with specific key
(public member function) [edit]
returns range of elements matching a specific key
(public member function) [edit]
returns an iterator to the first element not less than the given key
(public member function) [edit]
returns an iterator to the first element greater than the given key
(public member function) [edit]
Observers
returns the function that compares keys
(public member function) [edit]
returns the function that compares keys in objects of type value_type
(public member function) [edit]

Non-member functions

(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(removed in C++20)(C++20)
lexicographically compares the values of two sets
(function template) [edit]
specializes the std::swap algorithm
(function template) [edit]

Notes

The member types iterator and const_iterator may be aliases to the same type. This means defining a pair of function overloads using the two types as parameter types may violate the One Definition Rule. Since iterator is convertible to const_iterator, a single function with a const_iterator as parameter type will work instead.