std::unordered_set::find
From cppreference.com
< cpp | container | unordered set
| iterator find( const Key& key ); |
(1) | |
| const_iterator find( const Key& key ) const; |
(2) | |
| template< class K > iterator find( const K& x ); |
(3) | (since C++20) |
| template< class K > const_iterator find( const K& x ) const; |
(4) | (since C++20) |
1,2) Finds an element with key equivalent to
key. 3,4) Finds an element with key that compares equivalent to the value
x. This overload only participates in overload resolution if the qualified-id Hash::transparent_key_equal is valid and denotes a type. This assumes that such Hash is callable with both K and Key type, and that its key_equal is transparent, which, together, allows calling this function without constructing an instance of Key.Parameters
| key | - | key value of the element to search for |
| x | - | a value of any type that can be transparently compared with a key |
Return value
Iterator to an element with key equivalent to key. If no such element is found, past-the-end (see end()) iterator is returned.
Complexity
Constant on average, worst case linear in the size of the container.
Example
Run this code
#include <iostream> #include <unordered_set> int main() { // simple comparison demo std::unordered_set<int> example = {1, 2, 3, 4}; auto search = example.find(2); if (search != example.end()) { std::cout << "Found " << (*search) << '\n'; } else { std::cout << "Not found\n"; } }
Output:
Found 2
See also
| returns the number of elements matching specific key (public member function) | |
| returns range of elements matching a specific key (public member function) |