C++ multimap - value_comp() Function
The C++ multimap::value_comp function is used to compare two elements to get whether the key of the first one goes before the second.
Syntax
value_compare value_comp() const;
value_compare value_comp() const;
Parameters
No parameter is required.
Return Value
The comparison object associated to the container.
Time Complexity
Constant i.e, Θ(1).
Example:
In the example below, the multimap::value_comp function is used print all elements of the given multimap.
#include <iostream>
#include <map>
using namespace std;
int main (){
multimap<string, string> MMap;
multimap<string, string>::iterator it;
MMap.insert(pair<string, string>("USA", "New York"));
MMap.insert(pair<string, string>("CAN", "Toronto"));
MMap.insert(pair<string, string>("CAN", "Montreal"));
MMap.insert(pair<string, string>("IND", "Delhi"));
//creating a value_comp object
multimap<string, string>::value_compare MyComp = MMap.value_comp();
//printing the content of the multimap using value_comp object
it = MMap.begin();
cout<<"MMap contains:\n ";
do {
cout<<it->first<<" "<<it->second<<"\n ";
} while(MyComp(*it++, *MMap.rbegin()));
return 0;
}
The output of the above code will be:
MMap contains: CAN Toronto CAN Montreal IND Delhi USA New York
❮ C++ <map> Library
