未設定キーに対する値の参照

gistfile1.txt

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

int main()
{
    using namespace std;

    map<string, string> container;

    string &value1 = container["value1"];
    value1 = "value1";
    cout << "container[\"value1\"]: " << container["value1"] << endl;   // container["value1"]: value1
}