# Lookup

The following table provides additional information on the members of this template class.
Member | Description
--- | ---
iterator find(const key_type& k) | Returns: `iterator` pointing to item with key equivalent to `k`, or `end()` if no such item exists.
const_iterator find(const key_type& k) const | Returns: `const_iterator` pointing to item with key equivalent to `k`, or `end()` if no such item exists.
size_type count(const key_type& k) const | Returns: Number of items with keys equivalent to `k`.
std::pair<iterator, iterator> equal_range(const key_type& k) | Returns: Range containing all keys in the set that are equivalent to `k`.
std::pair<const_iterator, const_iterator> equal_range(const key_type& k) const | Returns: Range containing all keys in the set that are equivalent to `k`.

Parent topic: concurrent_unordered_set and concurrent_unordered_multiset Template Classes