std::vector<bool, Alloc>::reference
| class reference; |
||
The std::vector<bool, Alloc> specializations define std::vector<bool, Alloc>::reference as a publicly-accessible nested class. std::vector<bool, Alloc>::reference proxies the behavior of references to a single bit in std::vector<bool, Alloc>.
The primary use of std::vector<bool, Alloc>::reference is to provide an lvalue that can be returned from operator[].
Any reads or writes to a vector that happen via a std::vector<bool, Alloc>::reference potentially read or write to the entire underlying vector.
Member functions
| (constructor) |
constructs the reference. There is no default constructor. The copy constructor is implicitly declared(until C++11)defaulted(since C++11). There may be internal constructor that is accessible only to std::vector<bool, Alloc> itself. (public member function) |
| (destructor) |
destroys the reference (public member function) |
| operator= |
assigns a bool to the referenced bit (public member function) |
| operator bool |
returns the referenced bit (public member function) |
| flip |
flips the referenced bit (public member function) |
std::vector<bool, Alloc>::reference::~reference
~reference(); |
(until C++20) | |
| constexpr ~reference(); |
(since C++20) | |
Destroys the reference.
std::vector<bool, Alloc>::reference::operator=
| (1) | ||
reference& operator=( bool x ); |
(until C++11) | |
| reference& operator=( bool x ) noexcept; |
(since C++11) (until C++20) |
|
| constexpr reference& operator=( bool x ) noexcept; |
(since C++20) | |
| (2) | ||
reference& operator=( const reference& x ); |
(until C++11) | |
| reference& operator=( const reference& x ) noexcept; |
(since C++11) (until C++20) |
|
| constexpr reference& operator=( const reference& x ) noexcept; |
(since C++20) | |
| constexpr const reference& operator=( bool x ) const noexcept; |
(3) | (since C++23) |
Assigns a value to the referenced bit.
Parameters
| x | - | value to assign |
Return value
*this
std::vector<bool, Alloc>::reference::operator bool
operator bool() const; |
(until C++11) | |
| operator bool() const noexcept; |
(since C++11) (until C++20) |
|
| constexpr operator bool() const noexcept; |
(since C++20) | |
Returns the value of the referenced bit.
Parameters
(none)
Return value
The referenced bit.
std::vector<bool, Alloc>::reference::flip
void flip(); |
(until C++11) | |
| void flip() noexcept; |
(since C++11) (until C++20) |
|
| constexpr void flip() noexcept; |
(since C++20) | |
Inverts the referenced bit.
Parameters
(none)
Return value
(none)
Helper classes
std::formatter<std::vector<bool, Alloc>::reference>
| template< class T, class CharT > requires /*is-vector-bool-reference*/<T> |
(since C++23) | |
Specializes the std::formatter for std::vector<bool, Alloc>::reference. The specialization uses std::formatter<bool, CharT> as its underlying formatter (denoted as underlying_) where the referenced bit is converted to bool to be formatted.
The exposition-only constant /*is-vector-bool-reference*/<T> is true if and only if T denotes the type std::vector<bool, Alloc>::reference for some type Alloc and std::vector<bool, Alloc> is not a program-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) |
underlying_.parse(ctx);. underlying_.format(r, ctx);.
Example
| This section is incomplete Reason: no example |
See also
| access specified element (public member function of std::vector<T,Allocator>) | |
| [static] |
swaps two std::vector<bool>::references (public static member function) |
External links
"Effective Modern C++" by Scott Meyers (2015), Chapter 2, Item 6: "Use the explicitly typed initializer idiom when auto deduces undesired types." (p.43-46) — describes a possible misuse of the proxy class std::vector<bool>::reference).
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