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key_compare key_comp ( ) const;
Return comparison object
Returns the comparison object associated with the container, which can be used to compare two elements of the container.
This comparison object is set on object construction, and may either be a pointer to a function or an object of a class with a function call operator. In both cases it takes two arguments of the same type as the container elements, and returns true if the first argument is considered to go before the second in the strict weak ordering the object defines, and false otherwise.
In multiset containers, the element values are the keys themselves, therefore key_comp and its sibling member function value_comp both return the same.
Parameters
none
Return value
The comparison object.
multiset::key_compare is a member type defined to Compare, which is the second template parameter in the multiset class template.
Example
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// multiset::key_comp
#include <iostream>
#include <set>
using namespace std;
int main ()
{
multiset<int> mymultiset;
multiset<int>::key_compare mycomp;
multiset<int>::iterator it;
int i,highest;
mycomp = mymultiset.key_comp();
for (i=0; i<=5; i++) mymultiset.insert(i);
cout << "mymultiset contains:";
highest=*mymultiset.rbegin();
it=mymultiset.begin();
do {
cout << " " << *it;
} while ( mycomp(*it++,highest) );
cout << endl;
return 0;
}
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Output:
mymultiset contains: 0 1 2 3 4 5
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Complexity
Constant.
See also
| multiset::count | Count elements with a specific key (public member function) |
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