hash_map::find
Returns an iterator addressing the location of an element in a hash_map that has a key equivalent to a specified key.
iterator find(
const Key& _Key
);
const_iterator find(
const Key& _Key
) const;
Parameters
- _Key
The key value to be matched by the sort key of an element from the hash_map being searched.
Return Value
An iterator that addresses the location of an element with a specified key, or the location succeeding the last element in the hash_map if no match is found for the key.
Remarks
find returns an iterator that addresses an element in the hash_map whose sort key is equivalent to the argument key under a binary predicate that induces an ordering based on a less than comparability relation.
If the return value of find is assigned to a const_iterator, the hash_map object cannot be modified. If the return value of find is assigned to an iterator, the hash_map object can be modified
In Visual C++ .NET 2003, members of the <hash_map> and <hash_set> header files are no longer in the std namespace, but rather have been moved into the stdext namespace. See The stdext Namespace for more information.
Example
// hash_map_find.cpp
// compile with: /EHsc
#define _DEFINE_DEPRECATED_HASH_CLASSES 0
#include <hash_map>
#include <iostream>
int main( )
{
using namespace std;
using namespace stdext;
hash_map <int, int> hm1;
hash_map <int, int> :: const_iterator hm1_AcIter, hm1_RcIter;
typedef pair <int, int> Int_Pair;
hm1.insert ( Int_Pair ( 1, 10 ) );
hm1.insert ( Int_Pair ( 2, 20 ) );
hm1.insert ( Int_Pair ( 3, 30 ) );
hm1_RcIter = hm1.find( 2 );
cout << "The element of hash_map hm1 with a key of 2 is: "
<< hm1_RcIter -> second << "." << endl;
// If no match is found for the key, end( ) is returned
hm1_RcIter = hm1.find( 4 );
if ( hm1_RcIter == hm1.end( ) )
cout << "The hash_map hm1 doesn't have an element "
<< "with a key of 4." << endl;
else
cout << "The element of hash_map hm1 with a key of 4 is: "
<< hm1_RcIter -> second << "." << endl;
// The element at a specific location in the hash_map can be found
// using a dereferenced iterator addressing the location
hm1_AcIter = hm1.end( );
hm1_AcIter--;
hm1_RcIter = hm1.find( hm1_AcIter -> first );
cout << "The element of hm1 with a key matching "
<< "that of the last element is: "
<< hm1_RcIter -> second << "." << endl;
}
The element of hash_map hm1 with a key of 2 is: 20.
The hash_map hm1 doesn't have an element with a key of 4.
The element of hm1 with a key matching that of the last element is: 30.
Requirements
Header: <hash_map>
Namespace: stdext