C++ map 的两种插入数据方法

#include <map>
#include <iostream>

using namespace std;

int main() {
map<int, int> m1;
map<int, int>::iterator m1_Iter;

m1[1] = 20;
m1[4] = 40;
m1[3] = 60;
m1[2] = 50;
m1[1] = 40;
m1[7] = 30;

cout << "The original map m1 is:" << endl;
for (m1_Iter = m1.begin(); m1_Iter != m1.end(); m1_Iter++)｛
cout << m1_Iter->first << " " << m1_Iter->second << endl;
}
}

#include <map>
#include <iostream>

using namespace std;

int main() {
map<int, int> m1;
map<int, int>::iterator m1_Iter;

m1.insert(pair<int, int>(1, 20));
m1.insert(pair<int, int>(4, 40));
m1.insert(pair<int, int>(3, 60));
m1.insert(pair<int, int>(2, 50));
m1.insert(pair<int, int>(6, 40));
m1.insert(pair<int, int>(7, 30));

cout << "The original map m1 is:" << endl;
for (m1_Iter = m1.begin(); m1_Iter != m1.end(); m1_Iter++)｛
cout << m1_Iter->first << " " << m1_Iter->second << endl;
}
}