Map

template<
    class Key,
    class T,
    class Compare = std::less<Key>,
    class Allocator = std::allocator<std::pair<const Key, T> >
> class map;

std::map is a sorted associative container that contains key-value pairs with unique keys. Keys are sorted by using the comparison function Compare. Search, removal, and insertion operations have logarithmic complexity. Maps are usually implemented as red-black trees.

Everywhere the standard library uses the Compare requirements, 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).

Map_in_C++98

Member Type	Definition
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)
allocator_type	The fourth template parameter (Alloc)
reference	allocator_type::reference
const_reference	allocator_type::const_reference
pointer	allocator_type::pointer
const_pointer	allocator_type::const_pointer
iterator	a bidirectional iterator to value_type
const_iterator	a bidirectional iterator to const value_type
reverse_iterator	reverse_iterator
const_reverse_iterator	reverse_iterator<const_iterator>
difference_type	a signed integral type, identical to: iterator_traits::difference_type
size_type	an unsigned integral type that can represent any non-negative value of difference_type

Member Classes	Definition
value_compare	Nested function class to comapre objects of type value_type

Public Member Functions
constructor
destructor
operator=	Copy container content
Iterators:
begin	returns an iterator to the beginning
end	returns an iterator to the end
rbegin	returns a reverse iterator to the beginning
rend	returns a reverse iterator to the end
Capacity:
empty	checks whether the container is empty
size	return container size
max_size	return maximum size
Element access:
operator[]	access element
Modifiers:
insert	insert elements
erase	erase elements
swap	swaps content
clear	clears content
Observers:
key_comp	Return key comparison object
value_comp	Return value comparison object
Operations:
find	Get iterator to element
count	Count elements with a specific key
lower_bound	Return iterator to lower bound
upper_bound	Return iterator to upper bound
equal_range	Get range of equal elements
Allocator:
get_allocator	Get allocator

std::pair_C++98

template <class T1, class T2> struct pair;

This class couples together a pair of values, which may be of different types (T1 and T2). The individual values can be accessed through its public members first and second.

Pairs are a particular case of tuple(C++11).

Member types	Definition
first_type	The first template parameter (T1)
second_type	The second template parameter (T2)

Member variable	Definition
first	The first value in the pair
second	The second value in the pair

Public Member Functions
(constructor)	Construct pair
pair::operator=	Assign content
pair::swap	Swap content

Non-member function overloads
relational operators	Relational operators for pair (function template)