Re: any idear?

I want a class Table which saves one list of Pair<int,std::string>.
And I want that it has following behaviour:

Table t;//now t is empty
try{
    int i = t["me"];// I want this call to an empty table will throw a
exception [case 1]
}
catch(...){
   std::cout << "It's a empty table,bad operator" << std::endl;
    t["me"] = 0;//and i hope this call can work well [case 2]
}

Could some one tell me how to define this class Table?
How to define operator for case 1 and case 2?

class Table
{
public:
    class Bad_op{};
    struct Pair
    {
        int data;
        std::string str;
    };
    Table(const Table& table);
    Table();
    ~Table();
    Table& operator= (const Table& table);
    //int& operator[](const std::string& str);???????
    //nst int& operator[](const std::string& str)const;???????
private:
    std::vector<Pair> m_Vec;
};