include <iostream>

#include <map>

​

using namespace std;

​

int main(void) {

   map<char, int> m1;

   map<char, int> m2;

​

   if (m1 == m2)

      cout << "Both maps are equal." << endl;

​

   m1.emplace('a', 1);

​

   if (!(m1 == m2))

      cout << "Both maps are not equal." << endl;

​

   return 0;

}