std::unordered_set<Key,Hash,KeyEqual,Allocator>::bucket
From cppreference.com
< cpp | container | unordered set
| size_type bucket( const Key& key ) const; |
(1) | (since C++11) |
template< typename K > size_type bucket( const K& x ) const; |
(2) | (since C++26) |
1) Returns the index of the bucket for key key. Elements (if any) with keys equivalent to key are always found in this bucket.
2) Returns the index of the bucket for key that compares equivalent to the value x. Elements (if any) with keys that compare equivalent to x are always found in this bucket. This overload participates in overload resolution only if Hash::is_transparent and KeyEqual::is_transparent are valid and each denotes a type. This assumes that such
Hash is callable with both K and Key type, and that the KeyEqual is transparent, which, together, allows calling this function without constructing an instance of Key.The returned value is valid only for instances of the container for which bucket_count() returns the same value (e.g., rehash() invalidates previously obtained value).
The behavior is undefined if bucket_count() is zero.
Parameters
| key | - | the value of the key to examine |
| x | - | a value of any type that can be transparently compared with a key |
Return value
Bucket index for the requested key.
Complexity
Constant.
Notes
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_associative_heterogeneous_insertion |
202311L |
(C++26) | Heterogeneous overloads for the remaining member functions in ordered and unordered associative containers. (2) |
Example
| This section is incomplete Reason: no example |
See also
| returns the number of elements in specific bucket (public member function) |