vector<bool>::reference Class
The template<class Allocator> class vector< bool, allocator > reference class is a nested class in the vector<bool> Class whose objects are able to provide references to elements (single bits) within a vector<bool> object. C++ does not natively allow a reference to bits. But vector<bool> uses only one bit per element and these can be referenced using the objects in the nested class reference.
Requirements
Header: <vector>
Namespace: std
See Also
Reference
Thread Safety in the Standard C++ Library