std::map

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

int main()
{        
	map< int, int> mp1;  
	mp1.insert(map<int, int>::value_type(1,2));
	mp1.insert(map<int, int>::value_type(2, 5));
	mp1.insert(map<int, int>::value_type(3, 7));

	mp1[6] = 11;
	mp1[7] = 21;
	mp1[3] = 8;
	mp1[5] = 4;

	map<int, int> mp2;
	mp2[8] = 3;
	mp2[9] = 10;
	mp1.insert(mp2.begin(), mp2.end());

	for (auto itr = mp1.begin(); itr != mp1.end(); ++itr)
	{
		cout << itr->first << " " << itr->second << std::endl;
	}
	return 0;
}