hash_set::key_comp
Retrieves a copy of the hash traits object used to hash and order element key values in a hash_set.
key_compare key_comp( ) const;
Return Value
Returns the function object that a hash_set uses to order its elements, which is the template parameter Traits.
For more information on Traits see the hash_set Class topic.
Remarks
The stored object defines the member function:
bool operator(const Key& _xVal, const Key& _yVal);
which returns true if _xVal precedes and is not equal to _yVal in the sort order.
Note that both key_compare and value_compare are synonyms for the template parameter Traits. Both types are provided for the hash_set and hash_multiset classes, where they are identical, for compatibility with the hash_map and hash_multimap classes, where they are distinct.
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_set_key_comp.cpp
// compile with: /EHsc
#define _DEFINE_DEPRECATED_HASH_CLASSES 0
#include <hash_set>
#include <iostream>
int main( )
{
using namespace std;
using namespace stdext;
hash_set <int, hash_compare < int, less<int> > >hs1;
hash_set<int, hash_compare < int, less<int> > >::key_compare kc1
= hs1.key_comp( ) ;
bool result1 = kc1( 2, 3 ) ;
if( result1 == true )
{
cout << "kc1( 2,3 ) returns value of true, "
<< "where kc1 is the function object of hs1."
<< endl;
}
else
{
cout << "kc1( 2,3 ) returns value of false "
<< "where kc1 is the function object of hs1."
<< endl;
}
hash_set <int, hash_compare < int, greater<int> > > hs2;
hash_set<int, hash_compare < int, greater<int> > >::key_compare
kc2 = hs2.key_comp( ) ;
bool result2 = kc2( 2, 3 ) ;
if(result2 == true)
{
cout << "kc2( 2,3 ) returns value of true, "
<< "where kc2 is the function object of hs2."
<< endl;
}
else
{
cout << "kc2( 2,3 ) returns value of false, "
<< "where kc2 is the function object of hs2."
<< endl;
}
}
Output
kc1( 2,3 ) returns value of true, where kc1 is the function object of hs1.
kc2( 2,3 ) returns value of false, where kc2 is the function object of hs2.
Requirements
Header: <hash_set>
Namespace: stdext