Standard library header <set>

C++

Language

Headers

Freestanding and hosted implementations

Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

Standard Library header files

Language Support
<cstddef> <limits> <climits> <contract>	<cfloat> <cstdint> <new> <version>	<typeinfo> <exception> <initializer_list>	<csignal> <csetjmp> <cstdarg>
Concepts
<concepts>
Diagnostics
<stdexcept>	<cassert>	<cerrno>	<system_error>
General utilities
<utility> <memory> <memory_resource> <scoped_allocator> <compare>	<bitset> <tuple> <optional> <any> <variant>	<type_traits> <ratio> <chrono> <typeindex> <functional>	<ctime> <cstdlib>
Strings
<string> <string_view>	<cctype> <cwctype>	<cwchar> <cuchar>	<cstring> <charconv>
Localization
<locale>	<codecvt>	<clocale>
Containers
<span> <array> <vector>	<deque> <forward_list> <list>	<map> <set> <queue>	<unordered_map> <unordered_set> <stack>
Iterators
<iterator>
Algorithms
<algorithm>	<execution>
Numerics
<complex> <random>	<valarray> <numeric>	<cfenv> <cmath>	<bit>
Input/Output
<iosfwd> <ios> <iomanip> <streambuf>	<istream> <ostream> <iostream>	<sstream> <fstream> <syncstream>	<cstdio> <cinttypes> <strstream>
Regular expressions
<regex>
Filesystem support
<filesystem>
Thread support
<thread> <atomic>	<mutex> <shared_mutex>	<condition_variable> <future>
C compatibility
<ciso646> <cstdalign>	<cstdbool> <ccomplex>	<ctgmath>

This header is part of the containers library.

Includes
<initializer_list> (C++11)
Classes
set	collection of unique keys, sorted by keys (class template)
multiset	collection of keys, sorted by keys (class template)
Functions
operator==operator!=operator<operator<=operator>operator>=	lexicographically compares the values in the set (function template)
std::swap(std::set)	specializes the std::swap algorithm (function template)
operator==operator!=operator<operator<=operator>operator>=	lexicographically compares the values in the multiset (function template)
std::swap(std::multiset)	specializes the std::swap algorithm (function template)

Synopsis

#include <initializer_list>

namespace std
{
    template <class Key, class Compare = less<Key>,
              class Allocator = allocator<Key> >
        class set;

    template <class Key, class Compare, class Allocator>
        bool operator==(const set<Key,Compare,Allocator>& x,
                        const set<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator< (const set<Key,Compare,Allocator>& x,
                        const set<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator!=(const set<Key,Compare,Allocator>& x,
                        const set<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator> (const set<Key,Compare,Allocator>& x,
                        const set<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator>=(const set<Key,Compare,Allocator>& x,
                        const set<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator<=(const set<Key,Compare,Allocator>& x,
                        const set<Key,Compare,Allocator>& y);

    template <class Key, class Compare, class Allocator>
        void swap(set<Key,Compare,Allocator>& x,
                  set<Key,Compare,Allocator>& y);

    template <class Key, class Compare = less<Key>,
             class Allocator = allocator<Key> >
        class multiset;

    template <class Key, class Compare, class Allocator>
        bool operator==(const multiset<Key,Compare,Allocator>&
                        const multiset<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator< (const multiset<Key,Compare,Allocator>& x,
                        const multiset<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator!=(const multiset<Key,Compare,Allocator>& x,
                        const multiset<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator> (const multiset<Key,Compare,Allocator>& x,
                        const multiset<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator>=(const multiset<Key,Compare,Allocator>& x,
                        const multiset<Key,Compare,Allocator>& y);
    template <class Key, class Compare, class Allocator>
        bool operator<=(const multiset<Key,Compare,Allocator>& x,
                        const multiset<Key,Compare,Allocator>& y);

    template <class Key, class Compare, class Allocator>
        void swap(multiset<Key,Compare,Allocator>& x,
                  multiset<Key,Compare,Allocator>& y);
}

Class std::set

template <class Key, class Compare = less<Key>,
class Allocator = allocator<Key> >
class set
{
public:
    // types:
    typedef Key key_type;
    typedef Key value_type;
    typedef Compare key_compare;
    typedef Compare value_compare;
    typedef Allocator allocator_type;
    typedef value_type& reference;
    typedef const value_type& const_reference;
    typedef /*implementation-defined*/ iterator;
    typedef /*implementation-defined*/ const_iterator;
    typedef /*implementation-defined*/ size_type;
    typedef /*implementation-defined*/ difference_type;
    typedef typename allocator_traits<Allocator>::pointer pointer;
    typedef typename allocator_traits<Allocator>::const_pointer const_pointer;
    typedef std::reverse_iterator<iterator> reverse_iterator;
    typedef std::reverse_iterator<const_iterator> const_reverse_iterator;

    // construct/copy/destroy:
    explicit set(const Compare& comp = Compare(),
                 const Allocator& = Allocator());
    template <class InputIterator>
    set(InputIterator first, InputIterator last,
        const Compare& comp = Compare(), const Allocator& = Allocator());
    set(const set<Key,Compare,Allocator>& x);
    set(set<Key,Compare,Allocator>&& x);
    explicit set(const Allocator&);
    set(const set&, const Allocator&);
    set(set&&, const Allocator&);
    set(initializer_list<value_type>,
        const Compare& = Compare(),
        const Allocator& = Allocator());
    ~set();

    set<Key,Compare,Allocator>& operator= (const set<Key,Compare,Allocator>& x);
    set<Key,Compare,Allocator>& operator= (set<Key,Compare,Allocator>&& x);
    set& operator=(initializer_list<value_type>);
    allocator_type get_allocator() const noexcept;

    // iterators:
    iterator        begin() noexcept;
    const_iterator  begin() const noexcept;
    iterator        end() noexcept;
    const_iterator  end() const noexcept;

    reverse_iterator        rbegin() noexcept;
    const_reverse_iterator  rbegin() const noexcept;
    reverse_iterator        rend() noexcept;
    const_reverse_iterator  rend() const noexcept;

    const_iterator          cbegin() const noexcept;
    const_iterator          cend() const noexcept;
    const_reverse_iterator  crbegin() const noexcept;
    const_reverse_iterator  crend() const noexcept;

    // capacity:
    bool        empty() const noexcept;
    size_type   size() const noexcept;
    size_type   max_size() const noexcept;

    // modifiers:
    template <class... Args> pair<iterator, bool> emplace(Args&&... args);
    template <class... Args> 
        iterator emplace_hint(const_iterator position, Args&&... args);

    pair<iterator,bool> insert(const value_type& x);
    pair<iterator,bool> insert(value_type&& x);
    iterator insert(const_iterator position, const value_type& x);
    iterator insert(const_iterator position, value_type&& x);
    template <class InputIterator>
    void insert(InputIterator first, InputIterator last);
    void insert(initializer_list<value_type>);

    iterator erase(const_iterator position);
    size_type erase(const key_type& x);
    iterator erase(const_iterator first, const_iterator last);

    void swap(set<Key,Compare,Allocator>&);
    void clear() noexcept;

    // observers:
    key_compare   key_comp() const;
    value_compare value_comp() const;

    // set operations:
    iterator       find(const key_type& x);
    const_iterator find(const key_type& x) const;
    size_type      count(const key_type& x) const;
    iterator       lower_bound(const key_type& x);
    const_iterator lower_bound(const key_type& x) const;
    iterator       upper_bound(const key_type& x);
    const_iterator upper_bound(const key_type& x) const;
    pair<iterator,iterator> equal_range(const key_type& x);
    pair<const_iterator,const_iterator> equal_range(const key_type& x) const;
};

Class std::multiset

template <class Key, class Compare = less<Key>,
class Allocator = allocator<Key> >
class multiset
{
public:
    // types:
    typedef Key key_type;
    typedef Key value_type;
    typedef Compare key_compare;
    typedef Compare value_compare;
    typedef Allocator allocator_type;
    typedef value_type& reference;
    typedef const value_type& const_reference;
    typedef /*implementation-defined*/ iterator;
    typedef /*implementation-defined*/ const_iterator;
    typedef /*implementation-defined*/ size_type;
    typedef /*implementation-defined*/ difference_type;
    typedef typename allocator_traits<Allocator>::pointer pointer;
    typedef typename allocator_traits<Allocator>::const_pointer const_pointer;
    typedef std::reverse_iterator<iterator> reverse_iterator;
    typedef std::reverse_iterator<const_iterator> const_reverse_iterator;

    // construct/copy/destroy:
    explicit multiset(const Compare& comp = Compare(),
                 const Allocator& = Allocator());
    template <class InputIterator>
    multiset(InputIterator first, InputIterator last,
        const Compare& comp = Compare(), const Allocator& = Allocator());
    multiset(const multiset<Key,Compare,Allocator>& x);
    multiset(multiset<Key,Compare,Allocator>&& x);
    explicit multiset(const Allocator&);
    multiset(const multiset&, const Allocator&);
    multiset(multiset&&, const Allocator&);
    multiset(initializer_list<value_type>,
        const Compare& = Compare(),
        const Allocator& = Allocator());
    ~multiset();

    multiset<Key,Compare,Allocator>& operator= (const multiset<Key,Compare,Allocator>& x);
    multiset<Key,Compare,Allocator>& operator= (multiset<Key,Compare,Allocator>&& x);
    multiset& operator=(initializer_list<value_type>);
    allocator_type get_allocator() const noexcept;

    // iterators:
    iterator        begin() noexcept;
    const_iterator  begin() const noexcept;
    iterator        end() noexcept;
    const_iterator  end() const noexcept;

    reverse_iterator        rbegin() noexcept;
    const_reverse_iterator  rbegin() const noexcept;
    reverse_iterator        rend() noexcept;
    const_reverse_iterator  rend() const noexcept;

    const_iterator          cbegin() const noexcept;
    const_iterator          cend() const noexcept;
    const_reverse_iterator  crbegin() const noexcept;
    const_reverse_iterator  crend() const noexcept;

    // capacity:
    bool        empty() const noexcept;
    size_type   size() const noexcept;
    size_type   max_size() const noexcept;

    // modifiers:
    template <class... Args> pair<iterator, bool> emplace(Args&&... args);
    template <class... Args> 
        iterator emplace_hint(const_iterator position, Args&&... args);

    pair<iterator,bool> insert(const value_type& x);
    pair<iterator,bool> insert(value_type&& x);
    iterator insert(const_iterator position, const value_type& x);
    iterator insert(const_iterator position, value_type&& x);
    template <class InputIterator>
    void insert(InputIterator first, InputIterator last);
    void insert(initializer_list<value_type>);

    iterator erase(const_iterator position);
    size_type erase(const key_type& x);
    iterator erase(const_iterator first, const_iterator last);

    void swap(multiset<Key,Compare,Allocator>&);
    void clear() noexcept;

    // observers:
    key_compare   key_comp() const;
    value_compare value_comp() const;

    // multiset operations:
    iterator       find(const key_type& x);
    const_iterator find(const key_type& x) const;
    size_type      count(const key_type& x) const;
    iterator       lower_bound(const key_type& x);
    const_iterator lower_bound(const key_type& x) const;
    iterator       upper_bound(const key_type& x);
    const_iterator upper_bound(const key_type& x) const;
    pair<iterator,iterator> equal_range(const key_type& x);
    pair<const_iterator,const_iterator> equal_range(const key_type& x) const;
};