Материал из C\C++ эксперт
Count keys in multimap
#include <iostream>
using std::cout;
using std::endl;
#include <map>
int main()
{
std::multimap< int, double, std::less< int > > pairs; // declare the multimap pairs
cout << "There are currently " << pairs.count( 15 )
<< " pairs with key 15 in the multimap\n";
// insert two value_type objects in pairs
pairs.insert( std::multimap< int, double, std::less< int > >::value_type( 15, 2.7 ) );
pairs.insert( std::multimap< int, double, std::less< int > >::value_type( 15, 99.3 ) );
cout << "After inserts, there are " << pairs.count( 15 )
<< " pairs with key 15\n\n";
cout << endl;
return 0;
}
/*
There are currently 0 pairs with key 15 in the multimap
After inserts, there are 2 pairs with key 15
*/
