##### cppreference.com

##### Search

Create account

##### Namespaces

- Page
- Discussion

##### Variants

##### Views

- View
- Edit
- History

##### Actions

# std::unordered_multimap::count

From cppreference.com
< cpp‎ | container‎ | unordered multimap

[edit template]

size_type count( const Key& key ) const; | (1) | (since C++11)

Returns the number of elements with key `key`.

### [edit] Parameters

key | - | key value of the elements to count

### [edit] Return value

Number of elements with key `key`.

### [edit] Complexity

Constant on average, worst case linear in the size of the container.

### Notes

Typical implementations execute one constant-type hash lookup followed by as many equality comparisons as there are elements with the keys that compare equal to `key`, so the actual complexity is linear in the number of matching elements.

### [edit] See also

find | finds element with specific key (public member function) [edit]
equal_range | returns range of elements matching a specific key (public member function) [edit]

Retrieved from "http://en.cppreference.com/mwiki/index.php?title=cpp/container/unordered_multimap/count&oldid=65129"