Multimap

A multimap works exactly as a map, except that a multimap container will allow multiple values to be stored with the same key.

Let's explore the multimap container with a simple example:

#include <iostream>
#include <map>
#include <vector>
#include <iterator>
#include <algorithm>
using namespace std;

int main() {
  multimap< string, long > contacts = {
    { "Jegan", 2232342343 },
    { "Meena", 3243435343 },
    { "Nitesh", 6234324343 },
    { "Sriram", 8932443241 },
    { "Nitesh", 5534327346 }
  };

  auto pos = contacts.find ( "Nitesh" );
  int count = contacts.count( "Nitesh" );
  int index = 0;

  while ( pos != contacts.end() ) {
    cout << "\nMobile number of " << pos->first << " is " <<
    pos->second << endl;
    ++index;
    if ( index == count )
      break;
  }

  return 0;
}

The program can be compiled and the output can be viewed with the following commands:

g++ main.cpp -std=c++17

./a.out

The output of the program is as follows:

Mobile number of Nitesh is 6234324343
Mobile number of Nitesh is 5534327346