Namespaces
Variants
Views
Actions

Difference between revisions of "cpp/named req/SequenceContainer"

From cppreference.com
< cpp‎ | named req
(Correction: renaming emplace(p, t) to insert since there is no such emplace requirement (ref. [sequence.reqmts]))
(+missing requirements)
Line 5: Line 5:
  
 
===Requirements===
 
===Requirements===
−
{{dsc begin}}
 
−
{{dsc h1|Legend}}
 
−
{{dsc|{{ttb|X}}|Container type}}
 
−
{{dsc|{{ttb|T}}|Element type}}
 
−
{{dsc|{{ttb|a}}, {{ttb|b}}|Objects of type {{ttb|X}}}}
 
−
{{dsc|{{ttb|t}}|Object of type {{ttb|T}} }}
 
−
{{dsc|{{ttb|n}}|Positive integer}}
 
−
{{dsc|{{ttb|i}}, {{ttb|j}}|{{concept|InputIterator}}s denoting a valid range}}
 
−
{{dsc|{{ttb|il}}|{{lc|std::initializer_list}}<T>}}
 
−
{{dsc|{{ttb|args}}|Parameter pack}}
 
−
{{dsc|{{ttb|p}}, {{ttb|q}}|const_iterators in {{ttb|a}} }}
 
−
{{dsc end}}
 
  
 +
The type {{tt|X}} satisfies {{tt|SequenceContainer}} if
 +
 +
* The type {{tt|X}} satisfies {{concept|Container}}, and
 +
* The type {{tt|X::iterator}} satisfies {{concept|ForwardIterator}}, and
 +
* The type {{tt|X::const_iterator}} satisfies {{concept|ForwardIterator}}, and
 +
 +
Given
 +
* {{tt|T}}, the element type of {{tt|X}}
 +
* {{tt|A}}, the allocator type of {{tt|X}}: {{c|X::allocator_type}} if it exists, otherwise {{c|std::allocator<T>}}
 +
* {{tt|a}}, [[cpp/language/value_category|rvalue]] expression of type of type {{tt|X}}
 +
* {{tt|p}}, a valid const iterator into {{tt|a}}
 +
* {{tt|q}}, a valid dereferenceable const iterator into {{tt|a}}
 +
* {{tt|q1}} and {{tt|q2}}, two const iterators into {{tt|a}} such that {{c|[q1, q2)}} is a valid range
 +
* {{tt|i}} and {{tt|j}}, {{concept|InputIterator}}s such that {{c|[i, j)}} is a valid range and that the iterators refer to elements implicitly convertible to {{tt|value_type}}
 +
* {{tt|il}}, an object of type {{c|std::initializer_list<value_type>}}
 +
* {{tt|n}}, a value of type {{c|X::size_type}}
 +
* {{tt|t}}, an lvalue or const rvalue of type {{c|X::value_type}}
 +
* {{tt|rv}}, a non-const rvalue of type {{c|X::value_type}}
 +
* {{tt|Args}}: a template parameter pack
 +
* {{tt|args}}: a function parameter pack with the pattern {{c|Arg&&}}
 +
 +
The following expressions must be valid and have their specified effects for all sequence containers except {{lc|std::array}}:
  
 
{|class=wikitable
 
{|class=wikitable
 
!expression||return type||effects||precondition||postcondition
 
!expression||return type||effects||precondition||postcondition
 
|-
 
|-
−
|{{c|X(n,t)}}|| ||Constructs a {{ttb|SequenceContainer}} containing {{ttb|n}} copies of {{ttb|t}} || T {{concept|CopyInsertable}} || {{c|std::distance(begin(),end()) {{==}} n}}
+
|{{c|X(n, t)}}
 +
{{c|X a(n, t)}}
 +
|
 +
|Constructs the sequence container holding {{ttb|n}} copies of {{ttb|t}}
 +
|{{tt|T}} {{concept|CopyInsertable}} into {{tt|X}}
 +
|{{c|std::distance(begin(),end()) {{==}} n}}
 
|-
 
|-
−
|{{c|X(i,j)}}|| ||Constructs a {{ttb|SequenceContainer}} equivalent to the range {{tt|[i,j)}}
+
|{{c|X(i, j)}}
 +
{{c|X a(i, j)}}
 
|
 
|
−
* T {{concept|EmplaceConstructible}}  
+
|Constructs the sequence container equal, element-wise, to the range {{tt|[i,j)}}
−
* {{mark|only for std::vector}} If the iterators are not {{concept|ForwardIterator}}s, T must be {{concept|CopyInsertable}}
+
| {{tt|T}} is {{concept|EmplaceConstructible}} from {{tt|*i}} into {{tt|X}}
−
|{{c|1=std::distance(begin(),end()) ==  
+
{{mark|only for std::vector}} If the iterators are not {{concept|ForwardIterator}}s, T must be {{concept|CopyInsertable}}
−
std::distance(i,j)}}
+
|{{c|1=std::distance(begin(),end()) == std::distance(i,j)}}
 
|-
 
|-
−
|{{c|X(il)}}|| || {{c|X(il.begin(),il.end())}} || ||
+
|{{c|X(il)}}|| || {{c|X(il.begin(), il.end())}}>|| ||
 
|-
 
|-
−
|{{c|1=a = il}}||{{c|X&}}||Assigns the range represented by {{ttb|il}} into {{ttb|a}}
+
|{{c|1=a = il}}||{{c|X&}}||Assigns the range represented by {{ttb|il}} into {{ttb|a}}<ref>{{lc|std::array}} supports assignment from a braced-init-list, but not from an {{lc|std::initializer_list}}</ref>
 
| T {{concept|CopyInsertable}} and {{concept|CopyAssignable}}
 
| T {{concept|CopyInsertable}} and {{concept|CopyAssignable}}
 
| Existing elements of {{ttb|a}} are destroyed or assigned to
 
| Existing elements of {{ttb|a}} are destroyed or assigned to
 
|-  
 
|-  
−
|{{c|a.emplace(p,args)}}||iterator
+
|{{c|a.emplace(p,args)}}||{{tt|iterator}}
−
|Insert an object constructed with {{c|std::forward<Args>(args)}} before {{ttb|p}}
+
|Insert an object of type {{tt|T}}, constructed with {{c|std::forward<Args>(args)}} before {{ttb|p}}
−
|
+
|{{tt|T}} {{concept|CopyInsertable}}
−
*T {{concept|CopyInsertable}}
+
{{mark|for std::vector and std::deque}} {{tt|T}} {{concept|MoveAssignable}} and {{concept|MoveInsertable}}
−
*{{mark|for std::vector and std::deque}} T {{concept|MoveAssignable}} and {{concept|MoveInsertable}}
+
|Returned iterator points at the element constructed from {{tt|args}} into {{tt|a}}
−
|
+
 
|-  
 
|-  
−
|{{c|a.insert(p,t)}}||iterator
+
|{{c|a.insert(p,t)}}||{{tt|iterator}}
 
|Inserts a copy of {{ttb|t}} before {{ttb|p}}
 
|Inserts a copy of {{ttb|t}} before {{ttb|p}}
−
|
+
|{{tt|T}} {{concept|CopyInsertable}}
−
* T {{concept|CopyInsertable}}
+
{{mark|for std::vector and std::deque}} {{tt|T}} {{concept|CopyAssignable}} or {{concept|MoveAssignable}}
−
*{{mark|for std::vector and std::deque}} T {{concept|CopyAssignable}} or {{concept|MoveAssignable}}
+
|Returned iterator points at the copy of {{tt|t}} inserted into {{tt|a}}
−
|
+
|-
 +
|{{c|a.insert(p,rv)}}||{{tt|iterator}}
 +
|Inserts a copy of {{ttb|rv}} before {{ttb|p}}, possibly using move semantics
 +
|{{tt|T}} {{concept|MoveInsertable}}
 +
{{mark|for std::vector and std::deque}} {{tt|T}} {{concept|MoveAssignable}}
 +
|Returned iterator points at the copy of {{tt|rv}} inserted into {{tt|a}}
 
|-
 
|-
−
|{{c|a.insert(p,n,t)}}||iterator||Inserts {{ttb|n}} copies of {{ttb|t}} before {{ttb|p}}
+
|{{c|a.insert(p,n,t)}}||{{tt|iterator}}||Inserts {{ttb|n}} copies of {{ttb|t}} before {{ttb|p}}
−
| T {{concept|CopyInsertable}} and {{concept|CopyAssignable}}
+
|{{tt|T}} {{concept|CopyInsertable}} and {{concept|CopyAssignable}}
−
|
+
|Returned iterator points at the copy of the first element inserted into {{tt|a}} or is {{tt|p}} for {{c|1=n==0}}
 
|-
 
|-
−
|{{c|a.insert(p,i,j)}}||iterator||Inserts copies of elements in {{tt|[i, j)}} before {{ttb|p}}
+
|{{c|a.insert(p,i,j)}}||{{tt|iterator}}||Inserts copies of elements in {{tt|[i, j)}} before {{ttb|p}}
−
|
+
| T {{concept|EmplaceConstructible}} and {{ttb|i}} and {{ttb|j}} are not in {{ttb|a}}
−
* T {{concept|EmplaceConstructible}}
+
{{mark|only for std::vector}} If the iterators are not {{concept|ForwardIterator}}s, T must be {{concept|MoveInsertable}} and {{concept|MoveAssignable}}
−
* {{mark|only for std::vector}} If the iterators are not {{concept|ForwardIterator}}s, T must be {{concept|MoveInsertable}} and {{concept|MoveAssignable}}
+
|Each iterator in {{tt|[i,j)}} is dereferenced once. Returned iterator points at the copy of the first element inserted into {{tt|a}} or is {{tt|p}} for {{c|1=i==j}}
−
* {{ttb|i}} and {{ttb|j}} are not in {{ttb|a}}
+
−
|Each iterator in {{tt|[i,j)}} is dereferenced once
+
 
|-
 
|-
−
|{{c|a.insert(p, il)}}||iterator||{{c|a.insert(p,il.begin(),il.end())}}|| ||
+
|{{c|a.insert(p, il)}}||{{tt|iterator}}||{{c|a.insert(p,il.begin(),il.end())}}|| ||Returned iterator points at the copy of the first element inserted into {{tt|a}} or is {{tt|p}} if {{tt|il}} is empty.
 
|-
 
|-
−
|{{c|a.erase(q)}}||iterator||Erases the element pointed to by q
+
|{{c|a.erase(q)}}||{{tt|iterator}}||Erases the element pointed to by {{tt|q}}
 
|{{mark|std::deque, std::vector}} T {{concept|MoveAssignable}}
 
|{{mark|std::deque, std::vector}} T {{concept|MoveAssignable}}
−
|
+
|Returned iterator points at the element that was immediately following {{tt|q}} prior to erasure, or {{c|a.end()}} if no such element exists.
 
|-
 
|-
−
|{{c|a.erase(p,q)}}||iterator||Erases elements in {{tt|[p,q)}}||{{mark|std::deque, std::vector}} T {{concept|MoveAssignable}}||
+
|{{c|a.erase(q1,q2)}}||{{tt|iterator}}||Erases elements in {{tt|[p,q)}}||{{mark|std::deque, std::vector}} T {{concept|MoveAssignable}}||Returned iterator points at the element that was pointed by {{tt|q2}} prior to any erasure, or {{c|a.end()}} if no such element exists.
 
|-
 
|-
−
|{{c|a.clear()}}||void||Destroys all elements in {{ttb|a}}|| ||
+
|{{c|a.clear()}}||{{tt|void}}||Destroys all elements in {{ttb|a}}|| ||
−
* All references are invalidated
+
All references, pointers, and iterators are invalidated, including the end iterator. {{c|1=a.empty() == true}}.
−
* {{c|1=a.empty() == true}}
+
 
|-
 
|-
−
|{{c|a.assign(i,j)}}||void||Replaces elements in a with a copy of {{tt|[i, j)}}
+
|{{c|a.assign(i,j)}}||{{tt|void}}||Replaces elements in a with a copy of {{tt|[i, j)}}
−
|
+
|{{tt|T}} {{concept|EmplaceConstructible}} and {{ttb|i}}, {{ttb|j}} not in {{ttb|a}}
−
* T {{concept|EmplaceConstructible}}
+
{{mark|std::vector}} If not {{concept|ForwardIterator}}. {{tt|T}} {{concept|MoveInsertable}}
−
* {{mark|std::vector}} If not {{concept|ForwardIterator}} T {{concept|MoveInsertable}}
+
−
* {{ttb|i}}, {{ttb|j}} not in {{ttb|a}}
+
 
|Each iterator in {{tt|[i,j)}} is dereferenced once
 
|Each iterator in {{tt|[i,j)}} is dereferenced once
 
|-
 
|-
−
|{{c|a.assign(il)}}||void||{{c|a.assign(il.begin(),il.end())}}|| ||
+
|{{c|a.assign(il)}}||{{tt|void}}||{{c|a.assign(il.begin(),il.end())}}|| ||
 
|-
 
|-
−
|{{c|a.assign(n,t)}}||void
+
|{{c|a.assign(n,t)}}||{{tt|void}}
 
|Replaces elements in {{ttb|a}} with {{ttb|n}} copies of {{ttb|t}}
 
|Replaces elements in {{ttb|a}} with {{ttb|n}} copies of {{ttb|t}}
 
|T {{concept|CopyInsertable}} and {{concept|CopyAssignable}}
 
|T {{concept|CopyInsertable}} and {{concept|CopyAssignable}}
 
|
 
|
 
|-
 
|-
 +
!colspan=5|notes
 +
|-
 +
|colspan=5|<references/>
 +
|}
 +
 +
The following expressions must be valid and have their specified effects for the sequence containers named:
 +
 +
{|class=wikitable
 +
!expression||return type||effects||preconditions||containers
 +
|-
 +
|{{c|a.front()}}
 +
|{{tt|reference}}
 +
{{tt|const_reference}} for const a
 +
|Equivalent to {{c|*a.begin()}}
 +
|
 +
|(all)
 +
|-
 +
|{{c|a.back()}}
 +
|{{tt|void}}
 +
|Equivalent to {{c|1={ auto tmp = a.end(); --tmp; return *tmp; } }}
 +
|
 +
|{{lc|std::basic_string}} {{lc|std::array}} {{lc|std::deque}} {{lc|std::vector}}
 +
|-
 +
|{{c|a.emplace_front(args)}}
 +
|{{tt|void}}
 +
|Prepends a {{tt|T}} constructed with {{c|std::forward<Args>(args)...}}
 +
|{{tt|T}} {{concept|EmplaceConstructible}} into {{tt|X}} from {{tt|args}}
 +
|{{lc|std::deque}} {{lc|std::forward_list}} {{lc|std::list}}
 +
|-
 +
|{{c|a.emplace_back(args)}}
 +
|{{tt|void}}
 +
|Appends a {{tt|T}} constructed with {{c|std::forward<Args>(args)...}}
 +
|{{tt|T}} {{concept|EmplaceConstructible}} into {{tt|X}} from {{tt|args}}
 +
{{mark|std::vector only}} {{tt|T}} {{concept|MoveInsertable}} into {{tt|X}}
 +
|{{lc|std::deque}} {{lc|std::list}} {{lc|std::vector}}
 +
|-
 +
|{{c|a.push_font(t)}}
 +
|{{tt|void}}
 +
|Prepends a copy of {{tt|t}}
 +
|{{tt|T}} {{concept|CopyInsertable}} into {{tt|X}}
 +
|{{lc|std::deque}} {{lc|std::forward_list}} {{lc|std::list}}
 +
|-
 +
|{{c|a.push_front(rv)}}
 +
|{{tt|void}}
 +
|Prepends a copy of {{tt|rv}}, possibly using move semantics
 +
|{{tt|T}} {{concept|MoveInsertable}} into {{tt|X}}
 +
|{{lc|std::deque}} {{lc|std::forward_list}} {{lc|std::list}}
 +
|-
 +
|{{c|a.push_back(t)}}
 +
|{{tt|void}}
 +
|Appends a copy of {{tt|t}}
 +
|{{tt|T}} {{concept|CopyInsertable}} into {{tt|X}}
 +
|{{lc|std::basic_string}} {{lc|std::deque}} {{lc|std::list}} {{lc|std::vector}}
 +
|-
 +
|{{c|a.push_back(rv)}}
 +
|{{tt|void}}
 +
|Appends a copy of {{tt|rv}}, possibly using move semantics
 +
|{{tt|T}} {{concept|MoveInsertable}} into {{tt|X}}
 +
|{{lc|std::basic_string}} {{lc|std::deque}} {{lc|std::list}} {{lc|std::vector}}
 +
|-
 +
|{{c|a.pop_front()}}
 +
|{{tt|void}}
 +
|Destroys the first element.
 +
|{{c|1=a.empty() == false}}
 +
|{{lc|std::deque}} {{lc|std::forward_list}} {{lc|std::list}}
 +
|-
 +
|{{c|a.pop_back()}}
 +
|Destroys the last element
 +
|{{c|1=a.empty() == false}}
 +
|{{lc|std::basic_string}} {{lc|std::deque}} {{lc|std::list}} {{lc|std::vector}}
 +
|-
 +
|{{c|a[n]}}
 +
|{{tt|reference}}
 +
{{tt|const_reference}} for const a
 +
|Equivalent to {{c|*(n + a.begin())}}
 +
|
 +
|{{lc|std::basic_string}} {{lc|std::array}} {{lc|std::deque}} {{lc|std::vector}}
 +
|-
 +
|{{c|a.at(n)}}
 +
|{{tt|reference}}
 +
{{tt|const_reference}} for const a
 +
|Equivalent to {{c|*(n + a.begin())}}, except that {{lc|out_of_range}} is thrown if {{c|1=n>=size()}}
 +
|
 +
|{{lc|std::basic_string}} {{lc|std::array}} {{lc|std::deque}} {{lc|std::vector}}
 
|}
 
|}
  
−
===Optional Operations===
+
Additionally, for every sequence container, the constructor template that takes two input iterators and the member function template overloads of {{tt|insert()}}, {{tt|append()}}, {{tt|assign()}}, {{tt|replace()}} that take two input iterators do not participate in overload resolution if the their template arguments does not satisfy {{concept|InputIterator}}.
−
{{todo}}
+
  
 
===SequenceContainers in the standard library===
 
===SequenceContainers in the standard library===
 
{{dsc begin}}
 
{{dsc begin}}
 +
{{dsc inc | cpp/string/dsc basic_string}}
 
{{dsc inc | cpp/container/dsc array}}
 
{{dsc inc | cpp/container/dsc array}}
 
{{dsc inc | cpp/container/dsc vector}}
 
{{dsc inc | cpp/container/dsc vector}}

Revision as of 06:32, 20 March 2015

Template:cpp/concept/title Template:cpp/concept/navbar

A SequenceContainer is a Template:concept that stores objects of the same type in a linear arrangement.

Requirements

The type X satisfies SequenceContainer if

Given

  • T, the element type of X
  • A, the allocator type of X: X::allocator_type if it exists, otherwise std::allocator<T>
  • a, rvalue expression of type of type X
  • p, a valid const iterator into a
  • q, a valid dereferenceable const iterator into a
  • q1 and q2, two const iterators into a such that [q1, q2) is a valid range
  • i and j, Template:concepts such that [i, j) is a valid range and that the iterators refer to elements implicitly convertible to value_type
  • il, an object of type std::initializer_list<value_type>
  • n, a value of type X::size_type
  • t, an lvalue or const rvalue of type X::value_type
  • rv, a non-const rvalue of type X::value_type
  • Args: a template parameter pack
  • args: a function parameter pack with the pattern Arg&&

The following expressions must be valid and have their specified effects for all sequence containers except std::array:

expression return type effects precondition postcondition
X(n, t)

X a(n, t)

Constructs the sequence container holding n copies of t T Template:concept into X std::distance(begin(),end()) == n
X(i, j)

X a(i, j)

Constructs the sequence container equal, element-wise, to the range [i,j) T is Template:concept from *i into X

(only for std::vector) If the iterators are not Template:concepts, T must be Template:concept

std::distance(begin(),end()) == std::distance(i,j)
X(il) X(il.begin(), il.end())>
a = il X& Assigns the range represented by il into a[1] T Template:concept and Template:concept Existing elements of a are destroyed or assigned to
a.emplace(p,args) iterator Insert an object of type T, constructed with std::forward<Args>(args) before p T Template:concept

(for std::vector and std::deque) T Template:concept and Template:concept

Returned iterator points at the element constructed from args into a
a.insert(p,t) iterator Inserts a copy of t before p T Template:concept

(for std::vector and std::deque) T Template:concept or Template:concept

Returned iterator points at the copy of t inserted into a
a.insert(p,rv) iterator Inserts a copy of rv before p, possibly using move semantics T Template:concept

(for std::vector and std::deque) T Template:concept

Returned iterator points at the copy of rv inserted into a
a.insert(p,n,t) iterator Inserts n copies of t before p T Template:concept and Template:concept Returned iterator points at the copy of the first element inserted into a or is p for n==0
a.insert(p,i,j) iterator Inserts copies of elements in [i, j) before p T Template:concept and i and j are not in a

(only for std::vector) If the iterators are not Template:concepts, T must be Template:concept and Template:concept

Each iterator in [i,j) is dereferenced once. Returned iterator points at the copy of the first element inserted into a or is p for i==j
a.insert(p, il) iterator a.insert(p,il.begin(),il.end()) Returned iterator points at the copy of the first element inserted into a or is p if il is empty.
a.erase(q) iterator Erases the element pointed to by q (std::deque, std::vector) T Template:concept Returned iterator points at the element that was immediately following q prior to erasure, or a.end() if no such element exists.
a.erase(q1,q2) iterator Erases elements in [p,q) (std::deque, std::vector) T Template:concept Returned iterator points at the element that was pointed by q2 prior to any erasure, or a.end() if no such element exists.
a.clear() void Destroys all elements in a

All references, pointers, and iterators are invalidated, including the end iterator. a.empty() == true.

a.assign(i,j) void Replaces elements in a with a copy of [i, j) T Template:concept and i, j not in a

(std::vector) If not Template:concept. T Template:concept

Each iterator in [i,j) is dereferenced once
a.assign(il) void a.assign(il.begin(),il.end())
a.assign(n,t) void Replaces elements in a with n copies of t T Template:concept and Template:concept
notes
  1. ↑ std::array supports assignment from a braced-init-list, but not from an std::initializer_list

The following expressions must be valid and have their specified effects for the sequence containers named:

expression return type effects preconditions containers
a.front() reference

const_reference for const a

Equivalent to *a.begin() (all)
a.back() void Equivalent to { auto tmp = a.end(); --tmp; return *tmp; } std::basic_string std::array std::deque std::vector
a.emplace_front(args) void Prepends a T constructed with std::forward<Args>(args)... T Template:concept into X from args std::deque std::forward_list std::list
a.emplace_back(args) void Appends a T constructed with std::forward<Args>(args)... T Template:concept into X from args

(std::vector only) T Template:concept into X

std::deque std::list std::vector
a.push_font(t) void Prepends a copy of t T Template:concept into X std::deque std::forward_list std::list
a.push_front(rv) void Prepends a copy of rv, possibly using move semantics T Template:concept into X std::deque std::forward_list std::list
a.push_back(t) void Appends a copy of t T Template:concept into X std::basic_string std::deque std::list std::vector
a.push_back(rv) void Appends a copy of rv, possibly using move semantics T Template:concept into X std::basic_string std::deque std::list std::vector
a.pop_front() void Destroys the first element. a.empty() == false std::deque std::forward_list std::list
a.pop_back() Destroys the last element a.empty() == false std::basic_string std::deque std::list std::vector
a[n] reference

const_reference for const a

Equivalent to *(n + a.begin()) std::basic_string std::array std::deque std::vector
a.at(n) reference

const_reference for const a

Equivalent to *(n + a.begin()), except that out_of_range is thrown if n>=size() std::basic_string std::array std::deque std::vector

Additionally, for every sequence container, the constructor template that takes two input iterators and the member function template overloads of insert(), append(), assign(), replace() that take two input iterators do not participate in overload resolution if the their template arguments does not satisfy Template:concept.

SequenceContainers in the standard library

 stores and manipulates sequences of characters
(class template) [edit]
(C++11)
 fixed-sized inplace contiguous array
(class template) [edit]
dynamic contiguous array
(class template) [edit]
double-ended queue
(class template) [edit]
(C++11)
 singly-linked list
(class template) [edit]
doubly-linked list
(class template) [edit]

Trade-offs / usage notes

std::array Fast access but fixed number of elements
std::vector Fast access but mostly inefficient insertions/deletions
std::list
std::forward_list 		Efficient insertion/deletion in the middle of the sequence
std::deque Efficient insertion/deletion at the beginning and at the end of the sequence
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/named_req/SequenceContainer&oldid=77260"