What is a container in C++

, , No Comments

 Standard ContainersA container is a holder object that stores a collection of other objects (its elements). They are implemented as class templates, which allows a great flexibility in the types supported as elements.

The container manages the storage space for its elements and provides member functions to access them, either directly or through iterators (reference objects with similar properties to pointers).

Containers replicate structures very commonly used in programming: dynamic arrays (vector), queues (queue), stacks (stack), heaps (priority_queue), linked lists (list), trees (set), associative arrays (map)…

Many containers have several member functions in common, and share functionalities. The decision of which type of container to use for a specific need does not generally depend only on the functionality offered by the container, but also on the efficiency of some of its members (complexity). This is especially true for sequence containers, which offer different trade-offs in complexity between inserting/removing elements and accessing them.

stackqueue and priority_queue are implemented as container adaptors. Container adaptors are not full container classes, but classes that provide a specific interface relying on an object of one of the container classes (such as deque or list) to handle the elements. The underlying container is encapsulated in such a way that its elements are accessed by the members of the container adaptor independently of the underlying container class used.

Container class templates

Sequence containers:
array Array class (class template )vectorVector (class template )dequeDouble ended queue (class template )forward_list Forward list (class template )listList (class template )
Container adaptors:
stackLIFO stack (class template )queueFIFO queue (class template )priority_queuePriority queue (class template )
Associative containers:
setSet (class template )multisetMultiple-key set (class template )mapMap (class template )multimapMultiple-key map (class template )
Unordered associative containers:
unordered_set Unordered Set (class template )unordered_multiset Unordered Multiset (class template )unordered_map Unordered Map (class template )unordered_multimap Unordered Multimap (class template )
Other:
Two class templates share certain properties with containers, and are sometimes classified with them: bitset and valarray.

Member map

This is a comparison chart with the different member functions present on each of the different containers:

Legend:

C++98Available since C++98
C++11New in C++11

Sequence containers

Headers<array><vector><deque><forward_list><list>
Membersarrayvectordequeforward_listlist
constructorimplicitvectordequeforward_listlist
destructorimplicit~vector~deque~forward_list~list
operator=implicitoperator=operator=operator=operator=
iteratorsbeginbeginbeginbeginbegin
before_begin
begin
endendendendendend
rbeginrbeginrbeginrbeginrbegin
rendrendrendrendrend
const iteratorscbegincbegincbegincbegincbegin
cbefore_begin
cbegin
cendcendcendcendcendcend
crbegincrbegincrbegincrbegincrbegin
crendcrendcrendcrendcrend
capacitysizesizesizesizesize
max_sizemax_sizemax_sizemax_sizemax_sizemax_size
emptyemptyemptyemptyemptyempty
resizeresizeresizeresizeresize
shrink_to_fitshrink_to_fitshrink_to_fit
capacitycapacity
reservereserve
element accessfrontfrontfrontfrontfrontfront
backbackbackbackback
operator[]operator[]operator[]operator[]
atatatat
modifiersassignassignassignassignassign
emplaceemplaceemplaceemplace_afteremplace
insertinsertinsertinsert_afterinsert
eraseeraseeraseerase_aftererase
emplace_backemplace_backemplace_backemplace_back
push_backpush_backpush_backpush_back
pop_backpop_backpop_backpop_back
emplace_frontemplace_frontemplace_frontemplace_front
push_frontpush_frontpush_frontpush_front
pop_frontpop_frontpop_frontpop_front
clearclearclearclearclear
swapswapswapswapswapswap
list operationssplicesplice_aftersplice
removeremoveremove
remove_ifremove_ifremove_if
uniqueuniqueunique
mergemergemerge
sortsortsort
reversereversereverse
observersget_allocatorget_allocatorget_allocatorget_allocatorget_allocator
datadatadata

Associative containers

Headers<set><map><unordered_set><unordered_map>
Memberssetmultisetmapmultimapunordered_setunordered_multisetunordered_mapunordered_multimap
constructorsetmultisetmapmultimapunordered_setunordered_multisetunordered_mapunordered_multimap
destructor~set~multiset~map~multimap~unordered_set~unordered_multiset~unordered_map~unordered_multimap
assignmentoperator=operator=operator=operator=operator=operator=operator=operator=
iteratorsbeginbeginbeginbeginbeginbeginbeginbeginbegin
endendendendendendendendend
rbeginrbeginrbeginrbeginrbegin
rendrendrendrendrend
const iteratorscbegincbegincbegincbegincbegincbegincbegincbegincbegin
cendcendcendcendcendcendcendcendcend
crbegincrbegincrbegincrbegincrbegin
crendcrendcrendcrendcrend
capacitysizesizesizesizesizesizesizesizesize
max_sizemax_sizemax_sizemax_sizemax_sizemax_sizemax_sizemax_sizemax_size
emptyemptyemptyemptyemptyemptyemptyemptyempty
reservereservereservereservereserve
element accessatatat
operator[]operator[]operator[]
modifiersemplaceemplaceemplaceemplaceemplaceemplaceemplaceemplaceemplace
emplace_hintemplace_hintemplace_hintemplace_hintemplace_hintemplace_hintemplace_hintemplace_hintemplace_hint
insertinsertinsertinsertinsertinsertinsertinsertinsert
eraseeraseeraseeraseeraseeraseeraseeraseerase
clearclearclearclearclearclearclearclearclear
swapswapswapswapswapswapswapswapswap
operationscountcountcountcountcountcountcountcountcount
findfindfindfindfindfindfindfindfind
equal_rangeequal_rangeequal_rangeequal_rangeequal_rangeequal_rangeequal_rangeequal_rangeequal_range
lower_boundlower_boundlower_boundlower_boundlower_bound
upper_boundupper_boundupper_boundupper_boundupper_bound
observersget_allocatorget_allocatorget_allocatorget_allocatorget_allocatorget_allocatorget_allocatorget_allocatorget_allocator
key_compkey_compkey_compkey_compkey_comp
value_compvalue_compvalue_compvalue_compvalue_comp
key_eqkey_eqkey_eqkey_eqkey_eq
hash_functionhash_functionhash_functionhash_functionhash_function
bucketsbucketbucketbucketbucketbucket
bucket_countbucket_countbucket_countbucket_countbucket_count
bucket_sizebucket_sizebucket_sizebucket_sizebucket_size
max_bucket_countmax_bucket_countmax_bucket_countmax_bucket_countmax_bucket_count
hash policyrehashrehashrehashrehashrehash
load_factorload_factorload_factorload_factorload_factor
max_load_factormax_load_factormax_load_factormax_load_factormax_load_factor

0 टिप्पणियाँ:

Post a Comment