std::pair<iterator,iterator> equal_range( const Key& key ); | (1) | |
std::pair<const_iterator,const_iterator> equal_range( const Key& key ) const; | (2) | |
template< class K > std::pair<iterator,iterator> equal_range( const K& x ); | (3) | (since C++14) |
template< class K > std::pair<const_iterator,const_iterator> equal_range( const K& x ) const; | (4) | (since C++14) |
Returns a range containing all elements with the given key in the container. The range is defined by two iterators, one pointing to the first element that is not less than key and another pointing to the first element greater than key. Alternatively, the first iterator may be obtained with lower_bound(), and the second with upper_bound().
key.x. This overload only participates in overload resolution if the qualified-id Compare::is_transparent is valid and denotes a type. They allow calling this function without constructing an instance of Key. | key | - | key value to compare the elements to |
| x | - | alternative value that can be compared to Key |
std::pair containing a pair of iterators defining the wanted range: the first pointing to the first element that is not less than key and the second pointing to the first element greater than key.
If there are no elements not less than key, past-the-end (see end()) iterator is returned as the first element. Similarly if there are no elements greater than key, past-the-end iterator is returned as the second element.
| Since emplace and unhinted insert always insert at the upper bound, the order of equivalent elements in the equal range is the order of insertion unless hinted insert or emplace_hint was used to insert an element at a different position. | (since C++11) |
Logarithmic in the size of the container.
#include <iostream>
#include <map>
int main()
{
std::multimap<int, char> dict {
{1, 'A'},
{2, 'B'},
{2, 'C'},
{2, 'D'},
{4, 'E'},
{3, 'F'}
};
auto range = dict.equal_range(2);
for (auto i = range.first; i != range.second; ++i)
{
std::cout << i->first << ": " << i->second << '\n';
}
}Output:
2: B 2: C 2: D
| finds element with specific key (public member function) |
|
| returns an iterator to the first element greater than the given key (public member function) |
|
| returns an iterator to the first element not less than the given key (public member function) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
http://en.cppreference.com/w/cpp/container/multimap/equal_range