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std::unordered_multimap::find(3) | C++ Standard Libary | std::unordered_multimap::find(3) |
NAME¶
std::unordered_multimap::find - std::unordered_multimap::find
Synopsis¶
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 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.
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.
Notes¶
Feature-test macro: __cpp_lib_generic_unordered_lookup (for overloads (3,4))
Example¶
// Run this code
#include <iostream>
#include <unordered_map>
int main()
{
// simple comparison demo
std::unordered_multimap<int,char> example = {{1,'a'},{2,'b'}};
auto search = example.find(2);
if (search != example.end()) {
std::cout << "Found " << search->first <<
" " << search->second << '\n';
} else {
std::cout << "Not found\n";
}
}
Output:¶
Found 2 b
See also¶
count returns the number of elements matching specific key
(C++11) (public member function)
equal_range returns range of elements matching a specific key
(C++11) (public member function)
2022.07.31 | http://cppreference.com |