template:
template < class Key, // map::key_type
class T, // map::mapped_type
class Compare = less<Key>, // map::key_compare
class Alloc = allocator<pair<const Key,T> > // map::allocator_type
> class map;definition:
map specified by sequentially to storage elements and key element value binding.
In the map, it is often used to sort key, and each key is unique in the map. And mapping the type of key values may be different, and the packet type value_type members, this pair is a combination of the two types:
typedef pair<const Key, T> value_type;
Element in the interior, the map is always sorted in accordance with certain stringent conditions as weak ordering in accordance with an internal key comparison target (types Compare) indicated.
map container is typically single element access speed slower than the container unordered_map by their key, they allow direct iteration the subset according to their order.
In the map can be directly accessed using parentheses operator ((operator []) by a corresponding key.
map typically implemented as a binary search tree.
Attributes:
| Related | Associated container elements referenced by their key, they are not referenced by the absolute position in the container. |
| Sequence | Container elements always follow a strict order. All the elements are inserted in this order a given position. |
| Map | Each element will be a key to associate a mapping value: indicates the key identification element to the main content mapped values. |
| Key | The container of any two elements can have the same key. |
| Allocator-aware | Using a dispenser to a container object is handled dynamically its storage requirements. |
Template parameters:
| Key | The type of bond. Map of each element by its unique identification key. Alias is a member of type mapping :: key_type. |
| T | Type values map. Mapping each element will store some data for mapping values. Alias is a member of type mapping :: mapped_type. |
| Compare | In two key elements as arguments and returns a bool value. Expression compare (a, b) in, compare this type of object, a and b are the key, if a weak ordering function strictly defined, a is b is considered before, expression comp (a, b ) should return true. map object using this expression and to determine the order of the elements in the two key elements of the container are equal (compare them by reflex:!! If compare (a, b) && compare (b, a), they are equal ). map container of any two elements can have the same key. It can be a function pointer, the function may be an object (see constructor). This defaults to less <T>, it returns the results of the application is smaller than the operator (a <b) the same. Alias is a member of type mapping :: key_compare. |
| Alloc | The dispenser of the type defined in the object storage allocation model. By default, using the dispenser class template, which defines the most simple memory allocation model, and the value is irrelevant. Alias is a member of type mapping :: allocator_type. |
Member Type:
C++11：
| member type | definition | notes |
|---|---|---|
| key_type | The first template parameter (Key) | |
| mapped_type | The second template parameter (T) | |
| value_type | pair<const key_type,mapped_type> | |
| key_compare | The third template parameter (Compare) | defaults to: less<key_type> |
| value_compare | Nested function class to compare elements | see value_comp |
| allocator_type | The fourth template parameter (Alloc) | defaults to: allocator<value_type> |
| reference | value_type& | |
| const_reference | const value_type& | |
| pointer | allocator_traits<allocator_type>::pointer | for the default allocator: value_type* |
| const_pointer | allocator_traits<allocator_type>::const_pointer | for the default allocator: const value_type* |
| iterator | a bidirectional iterator to value_type | convertible to const_iterator |
| const_iterator | a bidirectional iterator to const value_type | |
| reverse_iterator | reverse_iterator<iterator> | |
| const_reverse_iterator | reverse_iterator<const_iterator> | |
| difference_type | a signed integral type, identical to: iterator_traits<iterator>::difference_type |
usually the same as ptrdiff_t |
| size_type | an unsigned integral type that can represent any non-negative value of difference_type | usually the same as size_t |
成员函数：
| (constructor) | Construct map (public member function ) |
| (destructor) | Construct map (public member function ) |
| operator= | Copy container content (public member function ) |
迭代器：
| begin | Return iterator to beginning (public member function ) |
| end | Return iterator to end (public member function ) |
| rbegin | Return reverse iterator to reverse beginning (public member function ) |
| rend | Return reverse iterator to reverse end (public member function ) |
| cbegin | Return const_iterator to beginning (public member function ) |
| cend | Return const_iterator to end (public member function ) |
| crbegin | Return const_reverse_iterator to reverse beginning (public member function ) |
| crend | Return const_reverse_iterator to reverse end (public member function ) |
容量：
| empty | Test whether container is empty (public member function ) |
| size | Return container size (public member function ) |
| max_size | Return maximum size (public member function ) |
获取元素：
| operator[] | Access element (public member function ) |
| at | Access element (public member function ) |
修改：
| insert | Insert elements (public member function ) |
| erase | Erase elements (public member function ) |
| swap | Swap content (public member function ) |
| clear | Clear content (public member function ) |
| emplace | Construct and insert element (public member function ) |
| emplace_hint | Construct and insert element with hint (public member function ) |
Observers：
| key_comp | Return key comparison object (public member function ) |
| value_comp | Return value comparison object (public member function ) |
操作：
| find | Get iterator to element (public member function ) |
| count | Count elements with a specific key (public member function ) |
| lower_bound | Return iterator to lower bound (public member function ) |
| upper_bound | Return iterator to upper bound (public member function ) |
| equal_range | Get range of equal elements (public member function ) |
Allocator:
| get_allocator | Get allocator (public member function ) |
