C++重载下标运算符(关键字到值的映射)

StaffList类：

class StaffList
{
    friend ostream& operator<<(ostream& o, const StaffList& s1);
public:
    //构造函数
    StaffList(int max = 10) :MaxSize(max), count(0)  //当前员工数为0
    {
        IdArr = new string[MaxSize];  //创建id的动态数组
        NameArr = new string[MaxSize];  //创建姓名的动态数组
    }
    //析构函数
    ~StaffList()
    {
        delete[] IdArr;
        delete[] NameArr;
    }
private:
    string* IdArr;  //员工id
    string* NameArr;  //员工姓名
    int count;   //当前员工数
    const int MaxSize;  //员工最多人数，即动态数组的大小
};

ostream& operator<<(ostream& o, const StaffList& s1)
{
    for (int i = 0; i < s1.count; i++)
    {
        cout << s1.IdArr[i] << ":" << s1.NameArr[i] << endl;
    }
    return o;
}

mian函数里的测试代码：

int main()
{   
    StaffList s1;
    //插入两条信息
    s1["A001"] = "Bob";
    s1["A002"] = "Klieam";
    cout << s1;
    cout << "-------------" << endl;

    //修改信息
    s1["A001"] = "Alice";
    s1["A002"] = "Kira";
    s1["A003"] = "David";
    cout << s1;
    return 0;
} 

运行效果： 

class StaffList
{
    friend ostream& operator<<(ostream& o, const StaffList& s1);
public:
    //构造函数
    StaffList(int max = 10) :MaxSize(max), count(0)  //当前员工数为0
    {
        IdArr = new string[MaxSize];  //创建id的动态数组
        NameArr = new string[MaxSize];  //创建姓名的动态数组
    }
    //析构函数
    ~StaffList()
    {
        delete[] IdArr;
        delete[] NameArr;
    }
    //重载的下标运算符
    string& operator[](const string& id)
    {
        int i;
        for (i = 0; i < count; i++)
        {
            if (IdArr[i] == id)
            {
                return NameArr[i];
            }
        }
        IdArr[i] = id;
        count++;
        return NameArr[i];
    }
private:
    string* IdArr;  //员工id
    string* NameArr;  //员工姓名
    int count;   //当前员工数
    const int MaxSize;  //员工最多人数，即动态数组的大小
};