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Difference between revisions of "cpp/container/vector bool"

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===Notes===
 
===Notes===
 
If the size of the bitset is known at compile time, {{c|std::bitset}} may be used, which offers a richer set of member functions. In addition, [http://www.boost.org/doc/libs/release/libs/dynamic_bitset/dynamic_bitset.html boost::dynamic_bitset] exists as an alternative to {{tt|std::vector<bool>}}.
 
If the size of the bitset is known at compile time, {{c|std::bitset}} may be used, which offers a richer set of member functions. In addition, [http://www.boost.org/doc/libs/release/libs/dynamic_bitset/dynamic_bitset.html boost::dynamic_bitset] exists as an alternative to {{tt|std::vector<bool>}}.
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{{c|std::vector<bool>}} does not not fulfill all container requirements because of proxy class {{c|std::vector<bool>::reference}}. Because of this proxy reference, the {{c|std::vector<bool>::iterator}} cannot be a {{concept|ForwardIterator}}. Therefore this iterator does not fulfill the {{concept|ForwardIterator}} requirement of some algorithms as for {{c|std::search}}. Consequently, this misuse can cause many problems... Moreover, depending on the implementation, they may not be a compile error or even a run-time error! (reference: [http://www.boost.org/doc/libs/1_52_0/libs/dynamic_bitset/dynamic_bitset.html#rationale boost])
  
 
[[de:cpp/container/vector bool]]
 
[[de:cpp/container/vector bool]]

Revision as of 05:27, 8 January 2013

 
C++
 
Containers library
 
std::vector<bool>
Member functions
Element access
Iterators
Capacity
Modifiers
std::vector<bool> specific
Non-member functions
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Helper classes
(C++11)
Deduction guides(C++17)
 
Defined in header <vector>
template<class Allocator = std::allocator<bool>>
class vector<bool, Allocator>;

std::vector<bool> is a 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 a byte-sized bool.

std::vector<bool> behaves similarly to std::vector, but in order to be space efficient, it:

  • Does not necessarily store its data in a single contiguous chunk of memory.
  • Exposes std::vector<bool>::reference as a method of accessing individual bits.
  • Does not use std::allocator_traits::construct to construct bit values.

Contents

Member types

Template:cpp/container/dcl list value typeTemplate:cpp/container/dcl list allocator typeTemplate:cpp/container/dcl list size typeTemplate:cpp/container/dcl list difference typeTemplate:cpp/container/dcl list const referenceTemplate:cpp/container/dcl list pointerTemplate:cpp/container/dcl list const pointerTemplate:cpp/container/dcl list iteratorTemplate:cpp/container/dcl list const iteratorTemplate:cpp/container/dcl list reverse iteratorTemplate:cpp/container/dcl list const reverse iterator
Member type Definition
proxy class representing a reference to a single bool
(class)

Member functions

Template:cpp/container/dcl list constructorTemplate:cpp/container/dcl list destructorTemplate:cpp/container/dcl list operator=Template:cpp/container/dcl list assignTemplate:cpp/container/dcl list get allocatorTemplate:cpp/container/dcl list atTemplate:cpp/container/dcl list operator atTemplate:cpp/container/dcl list frontTemplate:cpp/container/dcl list backTemplate:cpp/container/dcl list beginTemplate:cpp/container/dcl list endTemplate:cpp/container/dcl list rbeginTemplate:cpp/container/dcl list rendTemplate:cpp/container/dcl list emptyTemplate:cpp/container/dcl list sizeTemplate:cpp/container/dcl list max sizeTemplate:cpp/container/dcl list reserveTemplate:cpp/container/dcl list capacityTemplate:cpp/container/dcl list clearTemplate:cpp/container/dcl list insertTemplate:cpp/container/dcl list eraseTemplate:cpp/container/dcl list push backTemplate:cpp/container/dcl list pop backTemplate:cpp/container/dcl list resizeTemplate:cpp/container/dcl list swapTemplate:cpp/container/vector bool/dcl list flipTemplate:cpp/container/vector bool/dcl list swap
Element access
Iterators
Capacity
Modifiers
vector<bool> specific modifiers

Non-member functions

Template:cpp/container/dcl list operator cmpTemplate:cpp/container/dcl list swap2

Helper classes

Template:cpp/container/vector bool/dcl list hash

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>.

std::vector<bool> does not not fulfill all container requirements because of proxy class std::vector<bool>::reference. Because of this proxy reference, the std::vector<bool>::iterator cannot be a Template:concept. Therefore this iterator does not fulfill the Template:concept requirement of some algorithms as for std::search. Consequently, this misuse can cause many problems... Moreover, depending on the implementation, they may not be a compile error or even a run-time error! (reference: boost)

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