c++ map usage

#pragma once
#include <map>
#include <iostream>
using namespace std;
class MapTest
{
    
    
public:
	void DoTest()
	{
    
    
		map<int,int> t = map<int,int>();
		t.insert({
    
     2,11 });
		t.insert(pair<int,int>(3,22));
		t.insert(map<int,int>::value_type(2,33));
		t.insert({
    
     4,44 });
		t.erase(3);
		map<int, int>::iterator p = t.find(6);
		map<int, int>::iterator q = t.find(4);
		cout << "contains " << (p != t.end()) << " " << (q != t.end()) << endl;

		for (map<int,int>::iterator it = t.begin(); it != t.end(); it++)
		{
    
    
			cout << (*it).first << " " << (*it).second << endl;
		}
	}
};