escenciales stl

7/24/2019 Escenciales Stl

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class template

std::pairtemplate struct pair;

Pair of values

This class couples together a pair of values, which may be of different types (T1and T2). The individual values can be accessed through its

public members firstand second.

Pairs are a particular case of tuple.

Template parameters

T1

Type of member first, aliased as first_type.

T2

Type of member second, aliased as second_type.

Member types

member type definition notes

first_type The first template parameter (T1) Type of member first.

second_type The second template parameter (T2) Type of member second.

Member variables

member variable definition

first The first value in the pair

second The second value in the pair

Member functions

(constructor)

Construct pair (public member function )

pair::operator=

Assign contents (public member function )

pair::swap

Swap contents (public member function )

Non-member function overloads

relational operators (pair)

elational operators for pair (function template )

swap (pair)

!"changes the contents of two pairs (function template )

get (pair)

#et element (tuple interface) (function template )

Non-member class specializations

tuple_elementpair!

Tuple element type for pair (class template speciali$ation )

tuple_sizepair!

Tuple traits for pair (class template speciali$ation )

"ee also

ma#e_pair

Construct pair ob%ect (function template )

piecewise_construct

Piecewise construct constant (constant )

function template

std::make_pair
http://www.cplusplus.com/tuplehttp://www.cplusplus.com/tuplehttp://www.cplusplus.com/reference/utility/pair/pair/http://www.cplusplus.com/reference/utility/pair/operator=/http://www.cplusplus.com/reference/utility/pair/swap/http://www.cplusplus.com/reference/utility/pair/operators/http://www.cplusplus.com/reference/utility/pair/swap-free/http://www.cplusplus.com/reference/utility/pair/get/http://www.cplusplus.com/reference/utility/pair/tuple_element/http://www.cplusplus.com/reference/utility/pair/tuple_size/http://www.cplusplus.com/reference/utility/make_pair/http://www.cplusplus.com/reference/utility/piecewise_construct/http://www.cplusplus.com/reference/utility/pair/pair/http://www.cplusplus.com/reference/utility/pair/operator=/http://www.cplusplus.com/reference/utility/pair/swap/http://www.cplusplus.com/reference/utility/pair/operators/http://www.cplusplus.com/reference/utility/pair/swap-free/http://www.cplusplus.com/reference/utility/pair/get/http://www.cplusplus.com/reference/utility/pair/tuple_element/http://www.cplusplus.com/reference/utility/pair/tuple_size/http://www.cplusplus.com/reference/utility/make_pair/http://www.cplusplus.com/reference/utility/piecewise_construct/http://www.cplusplus.com/tuple


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C++98

C++

template pair make_pair (T1 x, T2 y);

Construct pair object

Constructs a pairobject with its frst element set toxand its second element set toy.

The template types can be implicitly deduced rom the arguments passed to make_pair.

pairobjects can be constructed rom otherpairobjects containing dierent types, i the respective types are

implicitly convertible.

C++9

C++!!

The behavior o this unction template is the same as i defned as"

1234

template pair make_pair (T1 x, T2 y) ! return( pair(x,y) ); "

#arameters

x, y

$alues or the members firstand second, respectively, o the pairobject being constructed.

%eturn value

& pairobject whose elements firstand secondare set toxandyrespectivelly.

The template parameters can be implicitly deduced.

'(ample

1234#$%&1'

1112131411#

make_pair exampleinclude std**pairinclude std**cout

intmain () ! std**pair foo; std**pair +ar;

foo std**make_pair (1',2'); +ar std**make_pair (1'-,./.); ok* implicit con0ersion from

pair

std**cout


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either or both- T1or T2is an rvalue referencetype o a type supporting move semantics, its corresponding

argument is modifed.

'(ception saety

The unction provides the same level o guarantees to each object as provided by the corresponding element

constructor.

Construct pair public member unction -

function template

std::$et (pair)

lvalue (1)

template typename tuple_element< 5, pair >**type6 7et (pair6 pr) noexcept;

rvalue (2)

template typename tuple_element< 5, pair >**type66 7et (pair66 pr) noexcept;

const (3)

template const typename tuple_element< 5, pair >**type6 7et (const pair6 pr) noexcept;

Get element (tuple interface)

%eturns a reerence to member firsti Iis ', or a reerence to member secondi Iis 1.

This overload o tuples homonym unction7etis provided so that pairobjects can be treated as a tuples. /or

that purpose, header also overloads tuple_sieand tuple_elementtypes with the appropriate

members defned.

Template parameters

5

#osition o an element in the pair, with 'identiying member first, and 1identiying member second.

si0e1tis an unsigned integral type.

T1, T2

Type o the elements in the pair.

/unction parameters

pr

& pairobject.

%eturn value

& reerence to a member o the pair.

/or rvaluepairobjects (2), the unction returns an rvalue referenceas i for8ardwas used-.

'(ample

1234
http://www.cplusplus.com/tuplehttp://www.cplusplus.com/gethttp://www.cplusplus.com/gethttp://www.cplusplus.com/pairhttp://www.cplusplus.com/tuplehttp://www.cplusplus.com/%3Cutility%3Ehttp://www.cplusplus.com/%3Cutility%3Ehttp://www.cplusplus.com/tuple_size%3Cpair%3Ehttp://www.cplusplus.com/tuple_element%3Cpair%3Ehttp://www.cplusplus.com/pairhttp://www.cplusplus.com/size_thttp://www.cplusplus.com/size_thttp://www.cplusplus.com/pairhttp://www.cplusplus.com/pairhttp://www.cplusplus.com/pairhttp://www.cplusplus.com/pairhttp://www.cplusplus.com/pairhttp://www.cplusplus.com/pairhttp://www.cplusplus.com/pairhttp://www.cplusplus.com/forwardhttp://www.cplusplus.com/tuplehttp://www.cplusplus.com/gethttp://www.cplusplus.com/pairhttp://www.cplusplus.com/tuplehttp://www.cplusplus.com/%3Cutility%3Ehttp://www.cplusplus.com/tuple_size%3Cpair%3Ehttp://www.cplusplus.com/tuple_element%3Cpair%3Ehttp://www.cplusplus.com/pairhttp://www.cplusplus.com/size_thttp://www.cplusplus.com/pairhttp://www.cplusplus.com/pairhttp://www.cplusplus.com/pairhttp://www.cplusplus.com/pairhttp://www.cplusplus.com/forward


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#$%&1'11121314

accessin7 pairs 8it 7etinclude std**pair, std**7et

include std**cout

intmain () ! std**pair foo (1',.x.);

std**7et


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header

%list&

List header

2eader that defnes the listcontainer class"

Classes

list

3ist class template -

/unctions

begin

terator to beginning unction template -

end

terator to end unction template -

function template

std::begin

C++

C++'

container (1) template auto +e7in (:ontainer6 cont) > decltype(cont-+e7in());

template auto +e7in (const :ontainer6 cont) > declty(cont-+e7in());

array (2) template T= +e7in (T(6arr)?);

Iterator to beginning

eturns an iterator pointing to the first element in the se&uence'

(1) Container

The function returns cont-+e7in().

(2) Array

The function returns the array-to-pointer conversionof its argument.

f the se&uence is empty, the returned value shall not be dereferenced.

These function templates are defined in multiple headers' !ach of these headers includes the generic templates for all container and array

types and not simply a specific overload. The headers

are',,,,,map,,,,,and .

Conversely,+e7inis overloaded (with a different definition) in headersand .

$arameters
http://www.cplusplus.com/listhttp://www.cplusplus.com/reference/list/list/http://www.cplusplus.com/reference/iterator/begin/http://www.cplusplus.com/reference/iterator/end/http://switch1.select%281%29/http://switch1.select%282%29/http://www.cplusplus.com/%3Citerator%3Ehttp://www.cplusplus.com/%3Citerator%3Ehttp://www.cplusplus.com/%3Citerator%3Ehttp://www.cplusplus.com/%3Carray%3Ehttp://www.cplusplus.com/%3Cdeque%3Ehttp://www.cplusplus.com/%3Cdeque%3Ehttp://www.cplusplus.com/%3Cforward_list%3Ehttp://www.cplusplus.com/%3Cforward_list%3Ehttp://www.cplusplus.com/%3Clist%3Ehttp://www.cplusplus.com/%3Clist%3Ehttp://www.cplusplus.com/%3Cmap%3Ehttp://www.cplusplus.com/%3Cmap%3Ehttp://www.cplusplus.com/%3Cmap%3Ehttp://www.cplusplus.com/%3Cregex%3Ehttp://www.cplusplus.com/%3Cregex%3Ehttp://www.cplusplus.com/%3Cset%3Ehttp://www.cplusplus.com/%3Cset%3Ehttp://www.cplusplus.com/%3Cset%3Ehttp://www.cplusplus.com/%3Cstring%3Ehttp://www.cplusplus.com/%3Cunordered_map%3Ehttp://www.cplusplus.com/%3Cunordered_map%3Ehttp://www.cplusplus.com/%3Cunordered_map%3Ehttp://www.cplusplus.com/%3Cunordered_set%3Ehttp://www.cplusplus.com/%3Cunordered_set%3Ehttp://www.cplusplus.com/%3Cunordered_set%3Ehttp://www.cplusplus.com/%3Cunordered_set%3Ehttp://www.cplusplus.com/%3Cvector%3Ehttp://www.cplusplus.com/beginhttp://www.cplusplus.com/beginhttp://www.cplusplus.com/beginhttp://www.cplusplus.com/%3Cinitializer_list%3Ehttp://www.cplusplus.com/%3Cinitializer_list%3Ehttp://www.cplusplus.com/%3Cinitializer_list%3Ehttp://www.cplusplus.com/%3Cvalarray%3Ehttp://www.cplusplus.com/listhttp://www.cplusplus.com/reference/list/list/http://www.cplusplus.com/reference/iterator/begin/http://www.cplusplus.com/reference/iterator/end/http://switch1.select%281%29/http://switch1.select%282%29/http://www.cplusplus.com/%3Citerator%3Ehttp://www.cplusplus.com/%3Carray%3Ehttp://www.cplusplus.com/%3Cdeque%3Ehttp://www.cplusplus.com/%3Cforward_list%3Ehttp://www.cplusplus.com/%3Clist%3Ehttp://www.cplusplus.com/%3Cmap%3Ehttp://www.cplusplus.com/%3Cregex%3Ehttp://www.cplusplus.com/%3Cset%3Ehttp://www.cplusplus.com/%3Cstring%3Ehttp://www.cplusplus.com/%3Cunordered_map%3Ehttp://www.cplusplus.com/%3Cunordered_set%3Ehttp://www.cplusplus.com/%3Cunordered_set%3Ehttp://www.cplusplus.com/%3Cvector%3Ehttp://www.cplusplus.com/beginhttp://www.cplusplus.com/%3Cinitializer_list%3Ehttp://www.cplusplus.com/%3Cvalarray%3E


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cont

An ob%ect of a class type for which member +e7inis defined.

arr

An array.

%eturn &alue

or (1), the same as returned by cont-+e7in().

or (2), a pointer to the first element in the array.

'ample

1234#$%&1'111213

1411#1$1%1&2'

std**+e7in std**end exampleinclude std**coutinclude std**0ector, std**+e7in, std**end

intmain () ! intfoo? !1',2',3',4','"; std**0ector +ar;

iterate foo* insertin7 into +ar for(autoit std**+e7in(foo); it@std**end(foo); AAit) +ar-pus_+ack(=it);

iterate +ar* print contents*

std**cout


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(1) Container

The function returns cont-end().

(2) Array

The function returns arrA.

f the se&uence is empty, the returned value compares e&ual to the one returned by+e7inwith the same argument.

These function templates are defined in multiple headers' !ach of these headers includes the generic templates for all container and arraytypes and not simply a specific overload. The headers

are',,,,,map,,,,,and .

Conversely,endis overloaded (with a different definition) in headersand.

$arameters

cont

An ob%ect of a class type for which member endis defined.

arr

An array.

%eturn &alue

or (1), the same as returned by cont-end().

or (2), a pointer to the element that would follow the last element in the array.

'ample

1234#$%&1'11

12131411#1$1%1&2'

std**+e7in std**end exampleinclude std**coutinclude std**0ector, std**+e7in, std**end

intmain () ! intfoo? !1',2',3',4','"; std**0ector +ar;

iterate foo* insertin7 into +ar for(autoit std**+e7in(foo); it@std**end(foo); AAit) +ar-pus_+ack(=it);

iterate +ar* print contents* std**cout


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class template

std::queuetemplate class 9ueue;

I! queue

*ueues are a type of container adaptor, specifically designed to operate in a * conte"t (firstin firstout), where elements are inserted into

one end of the container and e"tracted from the other.

*ueues are implemented as containers adaptors, which are classes that use an encapsulated ob%ect of a specific container class as

its underlying container, providing a specific set of member functions to access its elements. !lements arepushedinto the "back"of the

specific container andpoppedfrom its "front".

The underlying container may be one of the standard container class template or some other specifically designed container class. Thisunderlying container shall support at least the following operations'

empty

sie

front

+ack

pus_+ack

pop_front

The standard container classesde&ueandlistfulfill these re&uirements. -y default, if no container class is specified for a

particular 9ueueclass instantiation, the standard containerde&ueis used.

Template parameters

T

Type of the elements.Aliased as member type 9ueue**0alue_type.

:ontainer

Type of the internal underlying containerob%ect where the elements are stored.

ts 0alue_typeshall be T.

Aliased as member type 9ueue**container_type.

Member types

C/0

C11


0alue_type The first template parameter (T) Type of the elements

container_type The second template parameter (:ontainer) Type of the underlying container

sie_type an unsi$ned inte$ral type usually the same as si$e2t
http://www.cplusplus.com/dequehttp://www.cplusplus.com/dequehttp://www.cplusplus.com/listhttp://www.cplusplus.com/listhttp://www.cplusplus.com/listhttp://www.cplusplus.com/dequehttp://www.cplusplus.com/dequehttp://www.cplusplus.com/dequehttp://switch1.select%281%29/http://switch1.select%282%29/http://www.cplusplus.com/size_thttp://www.cplusplus.com/dequehttp://www.cplusplus.com/listhttp://www.cplusplus.com/dequehttp://switch1.select%281%29/http://switch1.select%282%29/http://www.cplusplus.com/size_t


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Member functions

(constructor)

Construct &ueue (public member function )

empty

Test whether container is empty (public member function )

size

eturn si$e (public member function )

front

Access ne"t element (public member function )

bac#Access last element (public member function )

pus+

nsert element (public member function )

emplace

Construct and insert element (public member function )

pop

emove ne"t element (public member function )

swap



relational operators

elational operators for &ueue (function )

swap (*ueue)

!"change contents of &ueues (public member function )


uses_allocator*ueue!

3ses allocator for &ueue (class template )

std::stac"template class stack;

LI! stac"

Stac4s are a type of container adaptor, specifically designed to operate in a 5* conte"t (lastin firstout), where elements are inserted ande"tracted only from one end of the container.

stac#s are implemented as containers adaptors, which are classes that use an encapsulated ob%ect of a specific container class as

its underlying container, providing a specific set of member functions to access its elements. !lements arepushed6poppedfrom the "back"ofthe specific container, which is 4nown as the topof the stac4.

The underlying container may be any of the standard container class templates or some other specifically designed container class. Thecontainer shall support the following operations'

empty

sie

+ack

pus_+ack

pop_+ack

The standard container classesvector,de&ueandlistfulfill these re&uirements. -y default, if no container class is specified for a

particular stackclass instantiation, the standard containerde&ueis used.
http://www.cplusplus.com/reference/queue/queue/queue/http://www.cplusplus.com/reference/queue/queue/empty/http://www.cplusplus.com/reference/queue/queue/size/http://www.cplusplus.com/reference/queue/queue/front/http://www.cplusplus.com/reference/queue/queue/back/http://www.cplusplus.com/reference/queue/queue/push/http://www.cplusplus.com/reference/queue/queue/emplace/http://www.cplusplus.com/reference/queue/queue/pop/http://www.cplusplus.com/reference/queue/queue/swap/http://www.cplusplus.com/reference/queue/queue/operators/http://www.cplusplus.com/reference/queue/queue/swap-free/http://www.cplusplus.com/reference/queue/queue/uses_allocator/http://www.cplusplus.com/vectorhttp://www.cplusplus.com/vectorhttp://www.cplusplus.com/dequehttp://www.cplusplus.com/dequehttp://www.cplusplus.com/listhttp://www.cplusplus.com/listhttp://www.cplusplus.com/listhttp://www.cplusplus.com/dequehttp://www.cplusplus.com/dequehttp://www.cplusplus.com/dequehttp://www.cplusplus.com/reference/queue/queue/queue/http://www.cplusplus.com/reference/queue/queue/empty/http://www.cplusplus.com/reference/queue/queue/size/http://www.cplusplus.com/reference/queue/queue/front/http://www.cplusplus.com/reference/queue/queue/back/http://www.cplusplus.com/reference/queue/queue/push/http://www.cplusplus.com/reference/queue/queue/emplace/http://www.cplusplus.com/reference/queue/queue/pop/http://www.cplusplus.com/reference/queue/queue/swap/http://www.cplusplus.com/reference/queue/queue/operators/http://www.cplusplus.com/reference/queue/queue/swap-free/http://www.cplusplus.com/reference/queue/queue/uses_allocator/http://www.cplusplus.com/vectorhttp://www.cplusplus.com/dequehttp://www.cplusplus.com/listhttp://www.cplusplus.com/deque


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Template parameters

T

Type of the elements.

Aliased as member type stack**0alue_type.

:ontainer

Type of the internal underlying containerob%ect where the elements are stored.ts 0alue_typeshall be T.

Aliased as member type stack**container_type.

Member types

C/0

C11


0alue_type The first template parameter (T) Type of the elements

container_type The second template parameter (:ontainer) Type of the underlying container

sie_type an unsi$ned inte$ral type usually the same as si$e2t

Member functions

(constructor)

Construct stac4 (public member function )

empty


size

eturn si$e (public member function )

top

Access ne"t element (public member function )

pus+

nsert element (public member function )emplace


pop

emove top element (public member function )

swap



relational operators

elational operators for stac4 (function )

swap (stac#)

!"change contents of stac4s (public member function )


uses_allocatorstac#!

3ses allocator for stac4 (class template )
http://switch1.select%281%29/http://switch1.select%282%29/http://www.cplusplus.com/size_thttp://www.cplusplus.com/reference/stack/stack/stack/http://www.cplusplus.com/reference/stack/stack/empty/http://www.cplusplus.com/reference/stack/stack/size/http://www.cplusplus.com/reference/stack/stack/top/http://www.cplusplus.com/reference/stack/stack/push/http://www.cplusplus.com/reference/stack/stack/emplace/http://www.cplusplus.com/reference/stack/stack/pop/http://www.cplusplus.com/reference/stack/stack/swap/http://www.cplusplus.com/reference/stack/stack/operators/http://www.cplusplus.com/reference/stack/stack/swap-free/http://www.cplusplus.com/reference/stack/stack/uses_allocator/http://switch1.select%281%29/http://switch1.select%282%29/http://www.cplusplus.com/size_thttp://www.cplusplus.com/reference/stack/stack/stack/http://www.cplusplus.com/reference/stack/stack/empty/http://www.cplusplus.com/reference/stack/stack/size/http://www.cplusplus.com/reference/stack/stack/top/http://www.cplusplus.com/reference/stack/stack/push/http://www.cplusplus.com/reference/stack/stack/emplace/http://www.cplusplus.com/reference/stack/stack/pop/http://www.cplusplus.com/reference/stack/stack/swap/http://www.cplusplus.com/reference/stack/stack/operators/http://www.cplusplus.com/reference/stack/stack/swap-free/http://www.cplusplus.com/reference/stack/stack/uses_allocator/


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std::settemplate < class T, set**key_type0alue_type class :ompare less, set**key_compare0alue_compare class /lloc allocator set**allocator_type > class set;

#et

Sets are containers that store uni&ue elements following a specific order.

n a set, the value of an element also identifies it (the value is itself the key, of type T), and each value must be uni&ue. The value of the

elements in a setcannot be modified once in the container (the elements are always const), but they can be inserted or removed from the

container.

nternally, the elements in a setare always sorted following a specificstrict weak orderingcriterion indicated by its internalcomparison

ob%ect(of type :ompare).

setcontainers are generally slower thanunordered2setcontainers to access individual elements by their key, but they allow the direct

iteration on subsets based on their order.

Sets are typically implemented as binary search trees.

,ontainer properties

Associative

!lements in associative containers are referenced by their keyand not by their absolute position in the container.

Ordered The elements in the container follow a strict order at all times. All inserted elements are given a position in this order.

Set

The value of an element is also the keyused to identify it.

Unique keys

+o two elements in the container can have e&uivalent keys.

Allocator-aware

The container uses an allocator ob%ect to dynamically handle its storage needs.

Template parameters

T

Type of the elements. !ach element in a setcontainer is also uni&uely identified by this value (each value is itself also the

element7s 4ey).

Aliased as member types set**key_typeand set**0alue_type.

:ompare

A binary predicate that ta4es two arguments of the same type as the elements and returns a +ool. The e"pressioncomp(a,+),

where compis an ob%ect of this type and aand bare 4ey values, shall return trueif ais considered to go before bin thestrict

weak orderingthe function defines.

The setob%ect uses this e"pression to determine both the order the elements follow in the container and whether two element 4eys

are e&uivalent (by comparing them refle"ively' they are e&uivalent if @comp(a,+) 66 @comp(+,a)). +o two elements in

a setcontainer can be e&uivalent.

This can be a function pointer or a function ob%ect (see constructorfor an e"ample). This defaults toless, which returns the

same as applying the less-than operator(a


12/19


key_type The first template parameter (T)

0alue_type The first template parameter (T)

key_compare The second template parameter (:ompare) defaults to: less

0alue_compare The second template parameter (:ompare) defaults to: less

allocator_type The third template parameter (/lloc)defaultsto:allocator

reference allocator_type**referencefor the

default allocator:0alue_type6

const_reference allocator_type**const_referencefor the

default allocator: const0alue_type6

pointer allocator_type**pointerfor thedefault allocator:0alue_type=

const_pointer allocator_type**const_pointerfor thedefault allocator: const0alue_type=

iterator a bidirectional iteratorto 0alue_typeconvertibleto const_iterator

const_iterator a bidirectional iteratorto const 0alue_type

re0erse_iterator reverse2iterator

const_re0erse_iterator reverse2iterator

difference_typea si$ned inte$ral type identicalto:iterator_traits**difference_type

usually the same as ptrdiff_t

sie_typean unsi$ned inte$ral type that can represent any nonne$ative value of difference_type

usually the same as si*e_t

Member functions

(constructor)

Construct set (public member function )

(destructor)

Set destructor (public member function )

operator=

Copy container content (public member function )

terators'

begin

eturn iterator to beginning (public member function )

end

eturn iterator to end (public member function )

rbegin

eturn reverse iterator to reverse beginning (public member function )

rend

eturn reverse iterator to reverse end (public member function )

cbegin

eturn const2iterator to beginning (public member function )

cend

eturn const2iterator to end (public member function )

crbegin

eturn const2reverse2iterator to reverse beginning (public member function )

crend

eturn const2reverse2iterator to reverse end (public member function )

,apacity'

empty
http://www.cplusplus.com/lesshttp://www.cplusplus.com/lesshttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/reverse_iteratorhttp://www.cplusplus.com/reverse_iteratorhttp://www.cplusplus.com/ptrdiff_thttp://www.cplusplus.com/size_thttp://www.cplusplus.com/reference/set/set/set/http://www.cplusplus.com/reference/set/set/~set/http://www.cplusplus.com/reference/set/set/operator=/http://www.cplusplus.com/reference/set/set/begin/http://www.cplusplus.com/reference/set/set/end/http://www.cplusplus.com/reference/set/set/rbegin/http://www.cplusplus.com/reference/set/set/rend/http://www.cplusplus.com/reference/set/set/cbegin/http://www.cplusplus.com/reference/set/set/cend/http://www.cplusplus.com/reference/set/set/crbegin/http://www.cplusplus.com/reference/set/set/crend/http://www.cplusplus.com/reference/set/set/empty/http://www.cplusplus.com/lesshttp://www.cplusplus.com/lesshttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/reverse_iteratorhttp://www.cplusplus.com/reverse_iteratorhttp://www.cplusplus.com/ptrdiff_thttp://www.cplusplus.com/size_thttp://www.cplusplus.com/reference/set/set/set/http://www.cplusplus.com/reference/set/set/~set/http://www.cplusplus.com/reference/set/set/operator=/http://www.cplusplus.com/reference/set/set/begin/http://www.cplusplus.com/reference/set/set/end/http://www.cplusplus.com/reference/set/set/rbegin/http://www.cplusplus.com/reference/set/set/rend/http://www.cplusplus.com/reference/set/set/cbegin/http://www.cplusplus.com/reference/set/set/cend/http://www.cplusplus.com/reference/set/set/crbegin/http://www.cplusplus.com/reference/set/set/crend/http://www.cplusplus.com/reference/set/set/empty/


13/19


size

eturn container si$e (public member function )

ma_size

eturn ma"imum si$e (public member function )

Modifiers'

insert

nsert element (public member function )erase

!rase elements (public member function )

swap

Swap content (public member function )

clear

Clear content (public member function )

emplace


emplace_+int

Construct and insert element with hint (public member function )

.bservers'

#ey_comp

eturn comparison ob%ect (public member function )

value_comp

eturn comparison ob%ect (public member function )

.perations'

find

#et iterator to element (public member function )

count

Count elements with a specific value (public member function )

lower_boundeturn iterator to lower bound (public member function )

upper_bound

eturn iterator to upper bound (public member function )

e*ual_range

#et range of e&ual elements (public member function )

/llocator'

get_allocator

#et allocator (public member function )
http://www.cplusplus.com/reference/set/set/size/http://www.cplusplus.com/reference/set/set/max_size/http://www.cplusplus.com/reference/set/set/insert/http://www.cplusplus.com/reference/set/set/erase/http://www.cplusplus.com/reference/set/set/swap/http://www.cplusplus.com/reference/set/set/clear/http://www.cplusplus.com/reference/set/set/emplace/http://www.cplusplus.com/reference/set/set/emplace_hint/http://www.cplusplus.com/reference/set/set/key_comp/http://www.cplusplus.com/reference/set/set/value_comp/http://www.cplusplus.com/reference/set/set/find/http://www.cplusplus.com/reference/set/set/count/http://www.cplusplus.com/reference/set/set/lower_bound/http://www.cplusplus.com/reference/set/set/upper_bound/http://www.cplusplus.com/reference/set/set/equal_range/http://www.cplusplus.com/reference/set/set/get_allocator/http://www.cplusplus.com/reference/set/set/size/http://www.cplusplus.com/reference/set/set/max_size/http://www.cplusplus.com/reference/set/set/insert/http://www.cplusplus.com/reference/set/set/erase/http://www.cplusplus.com/reference/set/set/swap/http://www.cplusplus.com/reference/set/set/clear/http://www.cplusplus.com/reference/set/set/emplace/http://www.cplusplus.com/reference/set/set/emplace_hint/http://www.cplusplus.com/reference/set/set/key_comp/http://www.cplusplus.com/reference/set/set/value_comp/http://www.cplusplus.com/reference/set/set/find/http://www.cplusplus.com/reference/set/set/count/http://www.cplusplus.com/reference/set/set/lower_bound/http://www.cplusplus.com/reference/set/set/upper_bound/http://www.cplusplus.com/reference/set/set/equal_range/http://www.cplusplus.com/reference/set/set/get_allocator/


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class template

std::maptemplate < class Bey, map**key_type class T, map**mapped_type class :ompare less, map**key_compare class /lloc allocator map**allocator_type > class map;

$ap

8aps are associative containers that store elements formed by a combination of a key valueand a mapped value, following a specific order.

n a map, the key valuesare generally used to sort and uni&uely identify the elements, while the mapped valuesstore the content associated

to this key. The types of keyand mapped valuemay differ, and are grouped together in member type0alue_type, which is apairtype

combining both'

typedefpair 0alue_type;

nternally, the elements in a mapare always sorted by its keyfollowing a specificstrict weak orderingcriterion indicated by its

internalcomparison ob%ect(of type :ompare).

mapcontainers are generally slower thanunordered2mapcontainers to access individual elements by their key, but they allow the direct

iteration on subsets based on their order.

The mapped values in amapcan be accessed directly by their corresponding 4ey using the bracket operator((operator9:).

8aps are typically implemented as binary search trees.

,ontainer properties

Associative

!lements in associative containers are referenced by their keyand not by their absolute position in the container.

Ordered

The elements in the container follow a strict order at all times. All inserted elements are given a position in this order.

Map

!ach element associates a keyto a mapped value' ;eys are meant to identify the elements whose main content is the mapped value.Unique keys

+o two elements in the container can have e&uivalent keys.

Allocator-aware

The container uses an allocator ob%ect to dynamically handle its storage needs.

Template parameters

Bey

Type of the keys. !ach element in a mapis uni&uely identified by its 4ey value.

Aliased as member type map**key_type.

T

Type of the mapped value. !ach element in a mapstores some data as its mapped value.

Aliased as member type map**mapped_type.:ompare

A binary predicate that ta4es two element 4eys as arguments and returns a +ool. The e"pression comp(a,+), where compis an

ob%ect of this type and aand bare 4ey values, shall return trueif ais considered to go before bin thestrict weak orderingthe

function defines.

The mapob%ect uses this e"pression to determine both the order the elements follow in the container and whether two element 4eys

are e&uivalent (by comparing them refle"ively' they are e&uivalent if @comp(a,+) 66 @comp(+,a)). +o two elements in

a mapcontainer can have e&uivalent 4eys.

This can be a function pointer or a function ob%ect (see constructorfor an e"ample). This defaults toless, which returns the

same as applying the less-than operator(a


15/19

Type of the allocator ob%ect used to define the storage allocation model. -y default, theallocatorclass template is used, which

defines the simplest memory allocation model and is valueindependent.Aliased as member type map**allocator_type.

Member types

C/0

C11


key_type The first template parameter (Bey)

mapped_type The second template parameter (T)

0alue_type pair

key_compare The third template parameter (:ompare) defaults to: less

0alue_compare Nested function class to compare elements see value_comp

allocator_type The fourth template parameter (/lloc)defaultsto:allocator

reference allocator_type**reference

for thedefault allocator:0alue_type6

const_reference allocator_type**const_referencefor thedefault allocator: const0alue_type6

pointer allocator_type**pointerfor thedefault allocator:0alue_type=

const_pointer allocator_type**const_pointerfor thedefault allocator: const0alue_type=

iterator a bidirectional iteratorto 0alue_typeconvertibleto const_iterator

const_iterator a bidirectional iteratorto const 0alue_typere0erse_iterator reverse2iterator

const_re0erse_iterator reverse2iterator

difference_typea si$ned inte$ral type identicalto:iterator_traits**difference_type

usually the same as ptrdiff_t

sie_typean unsi$ned inte$ral type that can represent any nonne$ative value of difference_type

usually the same as si*e_t

Member functions

(constructor)

Construct map (public member function )

(destructor)

8ap destructor (public member function )

operator=

Copy container content (public member function )

terators'

begin

eturn iterator to beginning (public member function )

end

eturn iterator to end (public member function )

rbegin
http://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://switch1.select%281%29/http://switch1.select%282%29/http://www.cplusplus.com/pairhttp://www.cplusplus.com/lesshttp://www.cplusplus.com/map::value_comphttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/reverse_iteratorhttp://www.cplusplus.com/reverse_iteratorhttp://www.cplusplus.com/ptrdiff_thttp://www.cplusplus.com/size_thttp://www.cplusplus.com/reference/map/map/map/http://www.cplusplus.com/reference/map/map/~map/http://www.cplusplus.com/reference/map/map/operator=/http://www.cplusplus.com/reference/map/map/begin/http://www.cplusplus.com/reference/map/map/end/http://www.cplusplus.com/reference/map/map/rbegin/http://www.cplusplus.com/allocatorhttp://switch1.select%281%29/http://switch1.select%282%29/http://www.cplusplus.com/pairhttp://www.cplusplus.com/lesshttp://www.cplusplus.com/map::value_comphttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/allocatorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/BidirectionalIteratorhttp://www.cplusplus.com/reverse_iteratorhttp://www.cplusplus.com/reverse_iteratorhttp://www.cplusplus.com/ptrdiff_thttp://www.cplusplus.com/size_thttp://www.cplusplus.com/reference/map/map/map/http://www.cplusplus.com/reference/map/map/~map/http://www.cplusplus.com/reference/map/map/operator=/http://www.cplusplus.com/reference/map/map/begin/http://www.cplusplus.com/reference/map/map/end/http://www.cplusplus.com/reference/map/map/rbegin/


16/19

eturn reverse iterator to reverse beginning (public member function )

rend

eturn reverse iterator to reverse end (public member function )

cbegin

eturn const2iterator to beginning (public member function )

cend

eturn const2iterator to end (public member function )

crbegin

eturn const2reverse2iterator to reverse beginning (public member function )

crendeturn const2reverse2iterator to reverse end (public member function )

,apacity'

empty


size

eturn container si$e (public member function )

ma_size

eturn ma"imum si$e (public member function )

'lement access'

operator01

Access element (public member function )

at

Access element (public member function )

Modifiers'

insert

nsert elements (public member function )

erase

!rase elements (public member function )

swap Swap content (public member function )

clear

Clear content (public member function )

emplace


emplace_+int

Construct and insert element with hint (public member function )

.bservers'

#ey_comp

eturn 4ey comparison ob%ect (public member function )

value_competurn value comparison ob%ect (public member function )

.perations'

find

#et iterator to element (public member function )

count

Count elements with a specific 4ey (public member function )

lower_bound

eturn iterator to lower bound (public member function )
http://www.cplusplus.com/reference/map/map/rend/http://www.cplusplus.com/reference/map/map/cbegin/http://www.cplusplus.com/reference/map/map/cend/http://www.cplusplus.com/reference/map/map/crbegin/http://www.cplusplus.com/reference/map/map/crend/http://www.cplusplus.com/reference/map/map/empty/http://www.cplusplus.com/reference/map/map/size/http://www.cplusplus.com/reference/map/map/max_size/http://www.cplusplus.com/reference/map/map/operator%5B%5D/http://www.cplusplus.com/reference/map/map/at/http://www.cplusplus.com/reference/map/map/insert/http://www.cplusplus.com/reference/map/map/erase/http://www.cplusplus.com/reference/map/map/swap/http://www.cplusplus.com/reference/map/map/clear/http://www.cplusplus.com/reference/map/map/emplace/http://www.cplusplus.com/reference/map/map/emplace_hint/http://www.cplusplus.com/reference/map/map/key_comp/http://www.cplusplus.com/reference/map/map/value_comp/http://www.cplusplus.com/reference/map/map/find/http://www.cplusplus.com/reference/map/map/count/http://www.cplusplus.com/reference/map/map/lower_bound/http://www.cplusplus.com/reference/map/map/rend/http://www.cplusplus.com/reference/map/map/cbegin/http://www.cplusplus.com/reference/map/map/cend/http://www.cplusplus.com/reference/map/map/crbegin/http://www.cplusplus.com/reference/map/map/crend/http://www.cplusplus.com/reference/map/map/empty/http://www.cplusplus.com/reference/map/map/size/http://www.cplusplus.com/reference/map/map/max_size/http://www.cplusplus.com/reference/map/map/operator%5B%5D/http://www.cplusplus.com/reference/map/map/at/http://www.cplusplus.com/reference/map/map/insert/http://www.cplusplus.com/reference/map/map/erase/http://www.cplusplus.com/reference/map/map/swap/http://www.cplusplus.com/reference/map/map/clear/http://www.cplusplus.com/reference/map/map/emplace/http://www.cplusplus.com/reference/map/map/emplace_hint/http://www.cplusplus.com/reference/map/map/key_comp/http://www.cplusplus.com/reference/map/map/value_comp/http://www.cplusplus.com/reference/map/map/find/http://www.cplusplus.com/reference/map/map/count/http://www.cplusplus.com/reference/map/map/lower_bound/


17/19

upper_bound

eturn iterator to upper bound (public member function )

e*ual_range

#et range of e&ual elements (public member function )

/llocator'

get_allocator

#et allocator (public member function )

public member function

std::map::map

C++98

C++

C++'

empty (1)

explicit map (const key_compare6 comp key_compare(), const allocator_type6 alloc allocator_type());

range (2)

template map (5nput5terator first, 5nput5terator last, const key_compare6 comp key_compare(), const allocator_type6 alloc allocator_type());

copy (3)map (const map6 x);

Construct map

Constructs a mapcontainer ob%ect, initiali$ing its contents depending on the constructor version used'

C/0

C11

(1) empty container constructor (deault constructor)

Constructs anemptycontainer, with no elements.

(2) ran!e constructor

Constructs a container with as many elements as the range first,last), with each element constructed from its

corresponding element in that range.

(") copy constructor

Constructs a container with a copy of each of the elements inx.

The container 4eeps an internal copy of allocand comp, which are used to allocate storage and to sort the elements throughout its lifetime.

The copy constructor (3)creates a container that 4eeps and uses copies ofx7sallocatorandcomparison ob%ect.

The storage for the elements is allocated using thisinternal allocator.

The elements are sorted according to the comparison ob%ect. f more than one element with e&uivalent 4eys is passed to the constructor, only

the first one is preserved.

$arameters

comp

-inary predicate that, ta4ing two element keysas argument, returns trueif the first argument goes before the second argument in

thestrict weak orderingit defines, and falseotherwise.

This shall be a function pointer or a function ob%ect.8ember type key_compareis the internal comparison ob%ect type used by the container, defined in mapas an alias of its third
http://www.cplusplus.com/reference/map/map/upper_bound/http://www.cplusplus.com/reference/map/map/equal_range/http://www.cplusplus.com/reference/map/map/get_allocator/http://www.cplusplus.com/reference/map/map/http://switch1.select%281%29/http://switch1.select%282%29/http://switch1.select%283%29/http://www.cplusplus.com/maphttp://www.cplusplus.com/maphttp://switch2.select%281%29/http://switch2.select%282%29/http://www.cplusplus.com/map::emptyhttp://www.cplusplus.com/map::emptyhttp://www.cplusplus.com/map::emptyhttp://www.cplusplus.com/map::get_allocatorhttp://www.cplusplus.com/map::get_allocatorhttp://www.cplusplus.com/map::get_allocatorhttp://www.cplusplus.com/map::key_comphttp://www.cplusplus.com/map::key_comphttp://www.cplusplus.com/map::key_comphttp://www.cplusplus.com/map::get_allocatorhttp://www.cplusplus.com/map::get_allocatorhttp://www.cplusplus.com/map::get_allocatorhttp://www.cplusplus.com/map::key_comphttp://www.cplusplus.com/maphttp://www.cplusplus.com/maphttp://www.cplusplus.com/reference/map/map/upper_bound/http://www.cplusplus.com/reference/map/map/equal_range/http://www.cplusplus.com/reference/map/map/get_allocator/http://www.cplusplus.com/reference/map/map/http://switch1.select%281%29/http://switch1.select%282%29/http://switch1.select%283%29/http://www.cplusplus.com/maphttp://switch2.select%281%29/http://switch2.select%282%29/http://www.cplusplus.com/map::emptyhttp://www.cplusplus.com/map::get_allocatorhttp://www.cplusplus.com/map::key_comphttp://www.cplusplus.com/map::get_allocatorhttp://www.cplusplus.com/map::key_comphttp://www.cplusplus.com/map


18/19

template parameter (:ompare).

f key_compareuses the default less(which has no state), this parameter is not relevant.

alloc

Allocator ob%ect.The container 4eeps and uses an internal copy of this allocator.

8ember type allocator_typeis the internal allocator type used by the container, defined inmapas an alias of its fourth

template parameter (/lloc).

f allocator_typeis an instantiation of the default allocator(which has no state), this parameter is not relevant.

first, last

nput iteratorsto the initial and final positions in a range. The range used is first,last), which includes all the elementsbetweenfirstand last, including the element pointed byfirstbut not the element pointed by last.

The function template argument 5nput5teratorshall be an input iteratortype that points to elements of a type from

which 0alue_typeob%ects can be constructed (inmap, 0alue_typeis an alias ofpair)

x

Anothermapob%ect of the same type (with the same class template arguments Bey, T, :ompareand /lloc), whose contents are

either copied or ac&uired.

il

An initiali$er2listob%ect.

These ob%ects are automatically constructed from initialier listdeclarators.8ember type 0alue_typeis the type of the elements in the container, defined inmapas an alias ofpair(seemap types).

'ample

1234#$%&1'1112

131411#1$1%1&2'2122232422#2$

2%2&3'31

constructin7 mapsinclude include

+oolfncomp (carls, carrs) !returnls


19/19

Constant for the empty constructors (1), and for the move constructors (!)(unless allocis different fromx7s allocator).

or all other cases, linear in the distance between the iterators (copy constructions) if the elements are already sorted according to the samecriterion. or unsorted se&uences, linearithmic (=lo7) in that distance (sorting,copy constructions).

terator validity

The move constructors(

escenciales stl

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