Array whose elements are indexed by key rather than positionally. We say that the array maps a key to its associated value.
associative container
A type that holds a collection of objects that supports efficient lookup by key.
key_type
Type defined by the associative containers that is the type for the keys used to store and retrieve values. For a map, key_type is the type used to index the map. For set, key_type and value_type are the same.
map
Associative container type that defines an associative array. Like vector, map is a class template. A map, however, is defined with two types: the type of the key and the type of the associated value. In a map a given key may appear only once. Each key is associated with a particular value. Dereferencing a map iterator yields a pair that holds a const key and its associated value.
mapped_type
Type defined by map and multimap that is the type for the values stored in the map.
multimap
Associative container similar to map except that in a multimap, a given key may appear more than once.
multiset
Associative container type that holds keys. In a multiset, a givenkey may appear more than once.
pair
Type that holds two public data members named first and second. The pair type is a template type that takes two type parameters that are used as the types of these members.
set
Associative container that holds keys. In a set, a given key may appear only once.
strict weak ordering
Relationship among the keys used in an associative container. In a strict weak ordering, it is possible to compare any two values and determine which of the two is less than the other. If neither value is less than the other, then the two values are considered equal. See Section 10.3.1 (p. 360).
value_type
The type of the element stored in a container. For set and multiset, value_type and key_type are the same. For map and multimap, this type is a pair whose first member has type const key_type and whose second member has type mapped_type.
* operator
The dereference operator when applied to a map, set, multimap, or multiset iterator yields a value_type. Note, that for map and multimap the value_type is a pair.
[] operator
Subscript operator. When applied to a map, [] takes an index that must be a key_type (or type that can be converted to key_type) value. Yields a mapped_type value.
