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 (public member function) |
|
(destructor) | destroys the reference (public member function) |
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operator= | assigns a value to the referenced bit (public member function) |
| returns the referenced bit (public member function) |
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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 by std::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) |
constexpr const reference& operator=( bool x ) const noexcept; | (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.
Parameters
| x | - | value to assign |
Return value
*this
std::vector<bool, Alloc>::reference::operator bool
operator bool() 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.
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 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) |
return underlying_.parse(ctx);.return underlying_.format(r, ctx);. Example
See also
| access specified element (public member function of std::vector<T,Allocator>) |
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[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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