标准库头文件 <unordered_map>

#include <initializer_list>
 
namespace std {
 
    // 类模板 unordered_map：
    template <class Key,
        class T,
        class Hash = hash<Key>,
        class Pred = std::equal_to<Key>,
        class Alloc = std::allocator<std::pair<const Key, T> > >
    class unordered_map;
 
    // 23.5.5，类模板 unordered_multimap：
    template <class Key,
        class T,
        class Hash = hash<Key>,
        class Pred = std::equal_to<Key>,
        class Alloc = std::allocator<std::pair<const Key, T> > >
    class unordered_multimap;
 
    template <class Key, class T, class Hash, class Pred, class Alloc>
    void swap(unordered_map<Key, T, Hash, Pred, Alloc>& x,
              unordered_map<Key, T, Hash, Pred, Alloc>& y);
    template <class Key, class T, class Hash, class Pred, class Alloc>
    void swap(unordered_multimap<Key, T, Hash, Pred, Alloc>& x,
              unordered_multimap<Key, T, Hash, Pred, Alloc>& y);
 
    template <class Key, class T, class Hash, class Pred, class Alloc>
    bool operator==(const unordered_map<Key, T, Hash, Pred, Alloc>& a,
                            const unordered_map<Key, T, Hash, Pred, Alloc>& b);
    template <class Key, class T, class Hash, class Pred, class Alloc>
    bool operator!=(const unordered_map<Key, T, Hash, Pred, Alloc>& a,
                        const unordered_map<Key, T, Hash, Pred, Alloc>& b);
    template <class Key, class T, class Hash, class Pred, class Alloc>
    bool operator==(const unordered_multimap<Key, T, Hash, Pred, Alloc>& a,
                            const unordered_multimap<Key, T, Hash, Pred, Alloc>& b);
    template <class Key, class T, class Hash, class Pred, class Alloc>
    bool operator!=(const unordered_multimap<Key, T, Hash, Pred, Alloc>& a,
                        const unordered_multimap<Key, T, Hash, Pred, Alloc>& b);
 
} // namespace std

template <class Key,
    class T,
    class Hash = hash<Key>,
    class Pred = std::equal_to<Key>,
    class Allocator = std::allocator<std::pair<const Key, T> > >
class unordered_map
{
public:
    // 类型
    typedef Key                                         key_type;
    typedef std::pair<const Key, T>                     value_type;
    typedef Hash                                        hasher;
    typedef Pred                                        key_equal;
    typedef Allocator                                   allocator_type;
    typedef typename allocator_type::pointer            pointer;
    typedef typename allocator_type::const_pointer      const_pointer;
    typedef typename allocator_type::reference          reference;
    typedef typename allocator_type::const_reference    const_reference;
    typedef /* 由实现定义 */                             size_type;
    typedef /* 由实现定义 */                             difference_type;
    typedef /* 由实现定义 */                             iterator;
    typedef /* 由实现定义 */                             const_iterator;
    typedef /* 由实现定义 */                             local_iterator;
    typedef /* 由实现定义 */                             const_local_iterator;
 
    // 构造/销毁/复制
    explicit unordered_map(size_type n = see below,
                           const hasher& hf = hasher(),
                           const key_equal& eql = key_equal(),
                           const allocator_type& a = allocator_type());
    template <class InputIterator>
    unordered_map(InputIterator f, InputIterator l,
                  size_type n = see below,
                  const hasher& hf = hasher(),
                  const key_equal& eql = key_equal(),
                  const allocator_type& a = allocator_type());
    unordered_map(const unordered_map&);
    unordered_map(unordered_map&&);
    explicit unordered_map(const Allocator&);
    unordered_map(const unordered_map&, const Allocator&);
    unordered_map(unordered_map&&, const Allocator&);
    unordered_map(initializer_list<value_type>,
                  size_type = see below,
                  const hasher& hf = hasher(),
                  const key_equal& eql = key_equal(),
                  const allocator_type& a = allocator_type());
    ~unordered_map();
    unordered_map& operator=(const unordered_map&);
    unordered_map& operator=(unordered_map&&);
    unordered_map& operator=(initializer_list<value_type>);
    allocator_type get_allocator() const noexcept;
 
    // 大小与容量
    bool empty() const noexcept;
    size_type size() const noexcept;
    size_type max_size() const noexcept;
 
    // 迭代器
    iterator       begin() noexcept;
    const_iterator begin() const noexcept;
    iterator       end() noexcept;
    const_iterator end() const noexcept;
    const_iterator cbegin() const noexcept;
    const_iterator cend() const noexcept;
 
    // 修改器
    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& obj);
    template <class P> pair<iterator, bool> insert(P&& obj);
    iterator insert(const_iterator hint, const value_type& obj);
    template <class P> iterator insert(const_iterator hint, P&& obj);
    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& k);
    iterator erase(const_iterator first, const_iterator last);
    void clear() noexcept;
 
    void swap(unordered_map&);
 
 
    // 观察器
    hasher hash_function() const;
    key_equal key_eq() const;
 
    // 查找
    iterator find(const key_type& k);
    const_iterator find(const key_type& k) const;
    size_type count(const key_type& k) const;
    std::pair<iterator, iterator>
    equal_range(const key_type& k);
    std::pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
    mapped_type& operator[](const key_type& k);
    mapped_type& operator[](key_type&& k);
    mapped_type& at(const key_type& k);
    const mapped_type& at(const key_type& k) const;
 
    // 桶接口
    size_type bucket_count() const noexcept;
    size_type max_bucket_count() const noexcept;
    size_type bucket_size(size_type n) const;
    size_type bucket(const key_type& k) const;
    local_iterator begin(size_type n);
    const_local_iterator begin(size_type n) const;
    local_iterator end(size_type n);
    const_local_iterator end(size_type n) const;
    const_local_iterator cbegin(size_type n) const;
    const_local_iterator cend(size_type n) const;
    // 散列策略
    float load_factor() const noexcept;
    float max_load_factor() const noexcept;
    void max_load_factor(float z);
    void rehash(size_type n);
    void reserve(size_type n);
};

template <class Key,
class T,
class Hash = hash<Key>,
class Pred = std::equal_to<Key>,
class Allocator = std::allocator<std::pair<const Key, T> > >
class unordered_multimap
{
public:
    // 类型
    typedef Key                                         key_type;
    typedef std::pair<const Key, T>                     value_type;
    typedef Hash                                        hasher;
    typedef Pred                                        key_equal;
    typedef Allocator                                   allocator_type;
    typedef typename allocator_type::pointer            pointer;
    typedef typename allocator_type::const_pointer      const_pointer;
    typedef typename allocator_type::reference          reference;
    typedef typename allocator_type::const_reference    const_reference;
    typedef /* 由实现定义 */                             size_type;
    typedef /* 由实现定义 */                             difference_type;
    typedef /* 由实现定义 */                             iterator;
    typedef /* 由实现定义 */                             const_iterator;
    typedef /* 由实现定义 */                             local_iterator;
    typedef /* 由实现定义 */                             const_local_iterator;
 
    // 构造/析构/复制
    explicit unordered_multimap(size_type n = see below,
                                const hasher& hf = hasher(),
                                const key_equal& eql = key_equal(),
                                const allocator_type& a = allocator_type());
    template <class InputIterator>
    unordered_multimap(InputIterator f, InputIterator l,
                       size_type n = see below,
                       const hasher& hf = hasher(),
                       const key_equal& eql = key_equal(),
                       const allocator_type& a = allocator_type());
    unordered_multimap(const unordered_multimap&);
    unordered_multimap(unordered_multimap&&);
    explicit unordered_multimap(const Allocator&);
    unordered_multimap(const unordered_multimap&, const Allocator&);
    unordered_multimap(unordered_multimap&&, const Allocator&);
    unordered_multimap(initializer_list<value_type>,
                       size_type = see below,
                       const hasher& hf = hasher(),
                       const key_equal& eql = key_equal(),
                       const allocator_type& a = allocator_type());
    ~unordered_multimap();
    unordered_multimap& operator=(const unordered_multimap&);
    unordered_multimap& operator=(unordered_multimap&&);
    unordered_multimap& operator=(initializer_list<value_type>);
    allocator_type get_allocator() const noexcept;
 
 
    // 大小与容量
    bool empty() const noexcept;
    size_type size() const noexcept;
    size_type max_size() const noexcept;
 
    // 迭代器
    iterator       begin() noexcept;
    const_iterator begin() const noexcept;
    iterator       end() noexcept;
    const_iterator end() const noexcept;
    const_iterator cbegin() const noexcept;
    const_iterator cend() const noexcept;
 
    // 修改器
    template <class... Args> iterator emplace(Args&&... args);
    template <class... Args> iterator emplace_hint(const_iterator position, Args&&... args);
    iterator insert(const value_type& obj);
    template <class P> iterator insert(P&& obj);
    iterator insert(const_iterator hint, const value_type& obj);
    template <class P> iterator insert(const_iterator hint, P&& obj);
    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& k);
    iterator erase(const_iterator first, const_iterator last);
    void clear() noexcept;
 
    void swap(unordered_multimap&);
 
 
 
    // 观察器
    hasher hash_function() const;
    key_equal key_eq() const;
 
    // 查找
    iterator find(const key_type& k);
    const_iterator find(const key_type& k) const;
    size_type count(const key_type& k) const;
    std::pair<iterator, iterator>
    equal_range(const key_type& k);
    std::pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
 
    // 桶接口
    size_type bucket_count() const noexcept;
    size_type max_bucket_count() const noexcept;
    size_type bucket_size(size_type n) const;
    size_type bucket(const key_type& k) const;
    local_iterator begin(size_type n);
    const_local_iterator begin(size_type n) const;
    local_iterator end(size_type n);
    const_local_iterator end(size_type n) const;
    const_local_iterator cbegin(size_type n) const;
    const_local_iterator cend(size_type n) const;
    // 散列策略
    float load_factor() const noexcept;
    float max_load_factor() const noexcept;
    void max_load_factor(float z);
    void rehash(size_type n);
    void reserve(size_type n);
};