C++ - Multimap size() Function
The C++ multimap::size function is used to find out the total number of elements in the multimap.
Note: Multimap is an ordered data container which implies all its elements are ordered all the time.
Syntax
size_type size() const;
size_type size() const noexcept;
Parameters
No parameter is required.
Return Value
Number of elements present in the multimap.
Time Complexity
Constant i.e, Θ(1).
Example:
In the below example, the multimap::size function is used find out the total number of elements in a multimap called MyMMap.
#include <iostream> #include <map> using namespace std; int main (){ multimap<string, string> MyMMap; MyMMap.insert(pair<string, string>("USA", "New York")); MyMMap.insert(pair<string, string>("USA", "Washington")); MyMMap.insert(pair<string, string>("CAN", "Toronto")); MyMMap.insert(pair<string, string>("CAN", "Montreal")); MyMMap.insert(pair<string, string>("IND", "Delhi")); cout<<"Multimap size is: "<<MyMMap.size()<<"\n\n"; cout<<"Add three key/element pairs in the Multimap.\n"; MyMMap.insert(pair<string, string>("UK", "London")); MyMMap.insert(pair<string, string>("IND", "Mumbai")); MyMMap.insert(pair<string, string>("USA", "Florida")); cout<<"Now, Multimap size is: "<<MyMMap.size()<<"\n"; return 0; }
The output of the above code will be:
Multimap size is: 5 Add three key/element pairs in the Multimap. Now, Multimap size is: 8
❮ C++ - Multimap