std::unordered_multimap<Key,T,Hash,KeyEqual,Allocator>::bucket - cppreference.com (original) (raw)

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 and KeyEqual are both transparent. 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.

[edit] Parameters

key - the value of the key to examine
x - a value of any type that can be transparently compared with a key

[edit] Return value

Bucket index for the requested key.

[edit] Complexity

Constant.

[edit] 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)

[edit] Example

[edit] See also

| | returns the number of elements in specific bucket (public member function) [edit] | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |