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