c++中map容器通过迭代器获取key和value

#include <iostream>
#include <map>
#include <string>


using namespace std;

class MyCompare
{
public:
  bool operator()(int v1, int v2)
  {
    return v1 > v2;
  }
};


int main()
{
  map<int, string> m;

  m.insert(pair<int, string>(1, "ddd"));
  m.insert(pair<int, string>(2, "ddd"));
  m.insert(pair<int, string>(3, "ddd"));
  

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

  system("pause");
  return 0;
}