std:: vector<bool>
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Defined in header
<vector>
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||
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template
<
class
Allocator
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||
std:: vector < bool > is a possibly space-efficient specialization of std::vector for the type bool .
The manner in which std:: vector < bool > is made space efficient (as well as whether it is optimized at all) is implementation defined. One potential optimization involves coalescing vector elements such that each element occupies a single bit instead of sizeof ( bool ) bytes.
std:: vector < bool > behaves similarly to std::vector , but in order to be space efficient, it:
- Does not necessarily store its elements as a contiguous array.
- Exposes class std:: vector < bool > :: reference as a method of accessing individual bits. In particular, objects of this class are returned by operator[] by value.
- Does not use std :: allocator_traits :: construct to construct bit values.
- Does not guarantee that different elements in the same container can be modified concurrently by different threads.
Member types
| Member type | Definition | ||||
value_type
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bool | ||||
allocator_type
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Allocator
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||||
size_type
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implementation-defined | ||||
difference_type
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implementation-defined | ||||
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proxy class representing a reference to a single bool
(class) |
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const_reference
|
bool | ||||
pointer
|
implementation-defined | ||||
const_pointer
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implementation-defined | ||||
iterator
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||||
const_iterator
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reverse_iterator
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std:: reverse_iterator < iterator > | ||||
const_reverse_iterator
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std:: reverse_iterator < const_iterator > |
Member functions
constructs the
vector
(public member function of
std::vector<T,Allocator>
)
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destructs the
vector
(public member function of
std::vector<T,Allocator>
)
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assigns values to the container
(public member function of
std::vector<T,Allocator>
)
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assigns values to the container
(public member function of
std::vector<T,Allocator>
)
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returns the associated allocator
(public member function of
std::vector<T,Allocator>
)
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Element access |
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access specified element with bounds checking
(public member function of
std::vector<T,Allocator>
)
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access specified element
(public member function of
std::vector<T,Allocator>
)
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access the first element
(public member function of
std::vector<T,Allocator>
)
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access the last element
(public member function of
std::vector<T,Allocator>
)
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Iterators |
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(C++11)
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returns an iterator to the beginning
(public member function of
std::vector<T,Allocator>
)
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(C++11)
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returns an iterator to the end
(public member function of
std::vector<T,Allocator>
)
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(C++11)
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returns a reverse iterator to the beginning
(public member function of
std::vector<T,Allocator>
)
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(C++11)
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returns a reverse iterator to the end
(public member function of
std::vector<T,Allocator>
)
|
Capacity |
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checks whether the container is empty
(public member function of
std::vector<T,Allocator>
)
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returns the number of elements
(public member function of
std::vector<T,Allocator>
)
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returns the maximum possible number of elements
(public member function of
std::vector<T,Allocator>
)
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reserves storage
(public member function of
std::vector<T,Allocator>
)
|
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returns the number of elements that can be held in currently allocated storage
(public member function of
std::vector<T,Allocator>
)
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Modifiers |
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clears the contents
(public member function of
std::vector<T,Allocator>
)
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inserts elements
(public member function of
std::vector<T,Allocator>
)
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(C++11)
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constructs element in-place
(public member function of
std::vector<T,Allocator>
)
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erases elements
(public member function of
std::vector<T,Allocator>
)
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adds an element to the end
(public member function of
std::vector<T,Allocator>
)
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(C++11)
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constructs an element in-place at the end
(public member function of
std::vector<T,Allocator>
)
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removes the last element
(public member function of
std::vector<T,Allocator>
)
|
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changes the number of elements stored
(public member function of
std::vector<T,Allocator>
)
|
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swaps the contents
(public member function of
std::vector<T,Allocator>
)
|
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flips all the bits
(public member function) |
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[static]
|
swaps two
std::vector<bool>::
reference
s
(public static member function) |
Non-member functions
|
(removed in C++20)
(removed in C++20)
(removed in C++20)
(removed in C++20)
(removed in C++20)
(C++20)
|
lexicographically compares the values of two
vector
s
(function template) |
|
specializes the
std::swap
algorithm
(function template) |
|
|
erases all elements satisfying specific criteria
(function template) |
Helper classes
|
(C++11)
|
hash support for
std::
vector
<
bool
>
(class template specialization) |
Deduction guides (C++17)
Notes
If the size of the bitset is known at compile time,
std::bitset
may be used, which offers a richer set of member functions. In addition,
boost::dynamic_bitset
exists as an alternative to
std::vector<bool>
.
Since its representation may be optimized, std:: vector < bool > does not necessarily meet all Container or SequenceContainer requirements. For example, because std:: vector < bool > :: iterator is implementation-defined, it may not satisfy the LegacyForwardIterator requirement. Use of algorithms such as std::search that require LegacyForwardIterator s may result in either compile-time or run-time errors .
The
Boost.Container version of
vector
does not specialize for
bool
.
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_containers_ranges
|
202202L | (C++23) | Ranges construction and insertion for containers |
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2187 | C++11 |
specializations for
bool
lacked
emplace
and
emplace_back
member functions
|
added |