C++ map demo

#include <iostream>
#include <map>
using namespace std;
int main() {
    map<int, string> person;
    person.insert(pair<int,string>(1,"bob"));
    person.insert(map<int, string>::value_type(2, "tony"));
    person.insert(pair<int, string>(3, "jack"));
    for (map<int,string>::iterator i= person.begin();i!= person.end();i++)
    {
        cout << i->first <<":"<< (i->second).c_str() << endl;
    }
    cout << "add 4 rose" << endl;
    person[4] = "rose";
    for (map<int, string>::iterator i = person.begin(); i != person.end(); i++)
    {
        cout << i->first << ":" << (i->second).c_str() << endl;
    }
    person.erase(1);
    cout << "erase bob" << endl;
    for (map<int, string>::iterator i = person.begin(); i != person.end(); i++)
    {
        cout << i->first << ":" << (i->second).c_str() << endl;
    }

    cout << "insert jack2" << endl;
    pair< map<int,string>::iterator,bool > pa = person.insert(pair<int, string>(3, "jack2"));
    if (!pa.second)
    {
        cout << "inset err" << endl;
    }
    for (map<int, string>::iterator i = person.begin(); i != person.end(); i++)
    {
        cout << i->first << ":" << (i->second).c_str() << endl;
    }

    cout << "person[3] = jack2" << endl;
    person[3] = "jack2";
    for (map<int, string>::iterator i = person.begin(); i != person.end(); i++)
    {
        cout << i->first << ":" << (i->second).c_str() << endl;
    }

    cout << "get 3" << endl;
    if (person.count(3))
    {
        cout << "R3:"<<person[3].c_str() << endl;
    }

    cout << "get 4" << endl;
    map<int, string>::iterator itmp = person.find(4);
    if (itmp != person.end())
    {
        cout << "R4:" << (itmp->second).c_str() << endl;
    }

    cout << "clear" << endl;
    person.clear();
    for (map<int, string>::iterator i = person.begin(); i != person.end(); i++)
    {
        cout << i->first << ":" << (i->second).c_str() << endl;
    }

    cout << "end press anykey." << endl;
    getchar();
}

显示：

1:bob
2:tony
3:jack
add 4 rose
1:bob
2:tony
3:jack
4:rose
erase bob
2:tony
3:jack
4:rose
insert jack2
inset err
2:tony
3:jack
4:rose
person[3] = jack2
2:tony
3:jack2
4:rose
get 3
R3:jack2
get 4
R4:rose
clear
end press anykey.