std::vector<bool, Alloc>::reference

From cppreference.com

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros(C++20)
Language support library
Concepts library(C++20)
Diagnostics library
Memory management library
Metaprogramming library(C++11)
General utilities library
Containers library
Iterators library
Ranges library(C++20)
Algorithms library
Strings library
Text processing library
Numerics library
Date and time library
Input/output library
Filesystem library(C++17)
Concurrency support library(C++11)
Execution control library(C++26)
Technical specifications
Symbols index
External libraries

[edit]

Containers library

node-handle (C++17)
Sequence
array (C++11)
vector
vector<bool>
inplace_vector (C++26)
hive (C++26)
deque
forward_list (C++11)
list
Associative
set
multiset
map
multimap
Unordered associative
unordered_set (C++11)
unordered_multiset (C++11)
unordered_map (C++11)
unordered_multimap (C++11)
Adaptors
stack
queue
priority_queue
flat_set (C++23)
flat_multiset (C++23)
flat_map (C++23)
flat_multimap (C++23)
Views
span (C++20)
mdspan (C++23)
Tables
Iterator invalidation
Member function table
Non-member function table

[edit]

std::vector<bool>

Member types

vector<bool>::reference

Member functions

vector::vector
vector::~vector
vector::operator=
vector::assign
vector::assign_range (C++23)
vector::get_allocator
Element access
vector::operator[]
vector::at
vector::front
vector::back
Iterators
vector::beginvector::cbegin (C++11)
vector::endvector::cend (C++11)
vector::rbeginvector::crbegin (C++11)
vector::rendvector::crend (C++11)

Capacity
vector::empty
vector::size
vector::max_size
vector::capacity
vector::resize
vector::reserve
vector::shrink_to_fit (DR*)
Modifiers
vector::clear
vector::erase
vector::insert
vector::insert_range (C++23)
vector::append_range (C++23)
vector::emplace (C++11)
vector::emplace_back (C++11)
vector::push_back
vector::pop_back
vector::swap
vector<bool>::flip
vector<bool>::swap

Non-member functions

operator==operator<=> (C++20)
swap(std::vector<bool>)
erase(std::vector<bool>)erase_if(std::vector<bool>) (C++20)(C++20)

operator!=operator<operator>operator<=operator>=

(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)

Helper classes

hash<std::vector<bool>>

(C++11)

Deduction guides(C++17)

[edit]

class reference;

Thestd::vector<bool, Alloc> specializations definestd::vector<bool, Alloc>::reference as a publicly-accessible nested class.std::vector<bool, Alloc>::reference proxies the behavior of references to a single bit instd::vector<bool, Alloc>.

The primary use ofstd::vector<bool, Alloc>::reference is to provide an assignable value that can be returned fromoperator[].

Any reads or writes to a vector that happen via astd::vector<bool, Alloc>::reference potentially read or write to the entire underlying vector.

[edit]Member functions

(constructor)	constructs the reference (public member function)
(destructor)	destroys the reference (public member function)
operator=	assigns a value to the referenced bit (public member function)
operator bool	returns the referenced bit (public member function)[edit]
flip	flips the referenced bit (public member function)

std::vector<bool, Alloc>::reference::reference

reference(const reference&)=default;		(since C++11) (constexpr since C++20)

Constructs the reference from another reference. The copy constructor is implicitly declared.(until C++11)

Other constructors can only be accessed bystd::vector<bool, Alloc>.

std::vector<bool, Alloc>::reference::~reference

~reference();		(constexpr since C++20)

Destroys the reference.

std::vector<bool, Alloc>::reference::operator=

reference& operator=(bool x);	(1)	(noexcept since C++11) (constexpr since C++20)
constexprconst reference& operator=(bool x)constnoexcept;	(2)	(since C++23)
reference& operator=(const reference& x);	(3)	(noexcept since C++11) (constexpr since C++20)

Assigns a value to the referenced bit.

The constoperator= enablesstd::vector<bool,Alloc>::iterator to satisfyoutput_iterator.

(since C++23)

Parameters

value to assign

Return value

*this

std::vector<bool, Alloc>::reference::operator bool

operatorbool()const;		(noexcept since C++11) (constexpr since C++20)

Returns the value of the referenced bit.

Return value

The referenced bit.

std::vector<bool, Alloc>::reference::flip

void flip();		(noexcept since C++11) (constexpr since C++20)

Inverts the referenced bit.

[edit]Helper classes

std::formatter<std::vector<bool, Alloc>::reference>

template<class T,class CharT> requires/is-vector-bool-reference/<T> struct formatter<T, CharT>;		(since C++23)

Specializes thestd::formatter forstd::vector<bool, Alloc>::reference. The specialization usesstd::formatter<bool, CharT> as its underlying formatter (denoted asunderlying_) where the referenced bit is converted tobool to be formatted.

The exposition-only constant/*is-vector-bool-reference*/<T> istrue if and only ifT denotes the typestd::vector<bool, Alloc>::reference for some typeAlloc andstd::vector<bool, Alloc> is not aprogram-defined specialization.

Member functions

template<class ParseContext> constexpr ParseContext::iterator parse( ParseContext& ctx);	(1)	(since C++23)
template<class FormatContext> FormatContext::iterator format(const T& r, FormatContext& ctx)const;	(2)	(since C++23)

1) Equivalent toreturn underlying_.parse(ctx);.

2) Equivalent toreturn underlying_.format(r, ctx);.

[edit]Example

This section is incomplete
Reason: no example

[edit]See also

operator[]	access specified element (public member function of`std::vector<T,Allocator>`)[edit]
swap [static]	swaps two`std::vector<bool>::``reference`s (public static member function)[edit]

[edit]External links

"Effective Modern C++" by Scott Meyers (2015), Chapter 2, Item 6: "Use the explicitly typed initializer idiom whenauto deduces undesired types." (p.43-46) — describes a possible misuse of the proxy classstd::vector<bool>::reference).

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/container/vector_bool/reference&oldid=182905"