multiset value_comp() method in C++ STL
Last Updated :
12 Jun, 2023
The std::multiset::value_comp is an inbuilt function in C++ STL which returns a copy of the comparison object used by the container. By default, this is a less object, which returns the same as operator ‘<‘.It is a function pointer or a function object which 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 it defines or false otherwise. Two keys are considered equivalent if key_comp returns false reflexively (i.e., no matter the order in which the keys are passed as arguments).
Syntax:
value_compare multiset_name.value_comp()
Parameters: This function does not accept any parameter.
Return value: The function returns a copy of the comparison object used by the container.
Below examples illustrate the above method:
Example 1:
CPP
#include <bits/stdc++.h>
using namespace std;
int main()
{
multiset<int> m;
multiset<int>::value_compare
comp
= m.value_comp();
m.insert(10);
m.insert(20);
m.insert(30);
m.insert(40);
cout << "Multiset has the elements\n";
int highest = *m.rbegin();
multiset<int>::iterator it = m.begin();
do {
cout << " " << *it;
} while (comp(*it++, highest));
return 0;
}
|
Output:
Multiset has the elements
10 20 30 40
Example 2:
CPP
#include <bits/stdc++.h>
using namespace std;
int main()
{
multiset<int> m;
multiset<int>::value_compare
comp
= m.value_comp();
m.insert(100);
m.insert(200);
m.insert(300);
m.insert(400);
cout << "Multiset has the elements\n";
int highest = *m.rbegin();
multiset<int>::iterator it = m.begin();
do {
cout << " " << *it;
} while (comp(*it++, highest));
return 0;
}
|
Output:
Multiset has the elements
100 200 300 400
Time complexity: O(n). // n is the size of the multiset.
Auxiliary space: O(1).
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