set::value_comp
Retrieves a copy of the comparison object used to order element values in a set.
value_compare value_comp( ) const;
Return Value
Returns the function object that a set uses to order its elements, which is the template parameter Traits.
For more information on Traits see the 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 value_compare and key_compare are synonyms for the template parameter Traits. Both types are provided for the set and multiset classes, where they are identical, for compatibility with the map and multimap classes, where they are distinct.
Example
// set_value_comp.cpp
// compile with: /EHsc
#include <set>
#include <iostream>
int main( )
{
using namespace std;
set <int, less<int> > s1;
set <int, less<int> >::value_compare vc1 = s1.value_comp( );
bool result1 = vc1( 2, 3 );
if( result1 == true )
{
cout << "vc1( 2,3 ) returns value of true, "
<< "where vc1 is the function object of s1."
<< endl;
}
else
{
cout << "vc1( 2,3 ) returns value of false, "
<< "where vc1 is the function object of s1."
<< endl;
}
set <int, greater<int> > s2;
set<int, greater<int> >::value_compare vc2 = s2.value_comp( );
bool result2 = vc2( 2, 3 );
if( result2 == true )
{
cout << "vc2( 2,3 ) returns value of true, "
<< "where vc2 is the function object of s2."
<< endl;
}
else
{
cout << "vc2( 2,3 ) returns value of false, "
<< "where vc2 is the function object of s2."
<< endl;
}
}
vc1( 2,3 ) returns value of true, where vc1 is the function object of s1.
vc2( 2,3 ) returns value of false, where vc2 is the function object of s2.
Requirements
Header: <set>
Namespace: std