hash_multimap::find
Note
This API is obsolete. The alternative is unordered_multimap Class.
Returns an iterator addressing the first location of an element in a hash_multimap 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 to be matched by the sort key of an element from the hash_multimap being searched.
Return Value
An iterator that addresses the first location of an element with a specified key, or the location succeeding the last element in the hash_multimap if no match is found for the key.
Remarks
The member function returns an iterator that addresses an element in the hash_multimap 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_multimap object cannot be modified. If the return value of find is assigned to an iterator, the hash_multimap 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_multimap_find.cpp
// compile with: /EHsc
#include <iostream>
#include <hash_map>
int main()
{
using namespace std;
using namespace stdext;
hash_multimap<int, int> hm1;
hash_multimap<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, 20));
hm1.insert(Int_Pair(3, 30));
hm1_RcIter = hm1.find(2);
cout << "The element of hash_multimap hm1 with a key of 2 is: "
<< hm1_RcIter -> second << "." << endl;
hm1_RcIter = hm1.find(3);
cout << "The first element of hash_multimap hm1 with a key of 3 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_multimap hm1 doesn't have an element "
<< "with a key of 4." << endl;
else
cout << "The element of hash_multimap hm1 with a key of 4 is: "
<< hm1_RcIter -> second << "." << endl;
// The element at a specific location in the hash_multimap 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 first element of hm1 with a key matching"
<< endl << "that of the last element is: "
<< hm1_RcIter -> second << "." << endl;
// Note that the first element with a key equal to
// the key of the last element is not the last element
if (hm1_RcIter == --hm1.end())
cout << "This is the last element of hash_multimap hm1."
<< endl;
else
cout << "This is not the last element of hash_multimap hm1."
<< endl;
}
The element of hash_multimap hm1 with a key of 2 is: 20. The first element of hash_multimap hm1 with a key of 3 is: 20. The hash_multimap hm1 doesn't have an element with a key of 4. The first element of hm1 with a key matching that of the last element is: 20. This is not the last element of hash_multimap hm1.
Requirements
Header: <hash_map>
Namespace: stdext