c++ - input a value then use that value as input -

i trying input , use input value cin value. these codes cannot compiled (expected), illustrate idea:

class stafflogin : public sharedata { private:     string id;     void authorized()     {         struct staffs         {             string username;             string password;         };         staffs id700014089, id700014090;         id700014089.username="robin";         id700014089.password="c++ fun";         cin>>id;         cout<<"username: ";         cin>>"id".username;         cout<<"password: ";         cin>>"id".password;     } }; 

for example, want id user, cin>>id . use value in input (cin>>"the id previous cin".username) can create new id, username , password new user. please tell me if there method it?

edit: ok found simpler solution using map<string,string> stafflist; map<string,string>::iterator it; without struct. comment in case of need more details. ;)

c++ not dynamic language, create objects dynamically names supplied user input need use kind of key-value container let's associate arbitrary names objects. standard solutions in c++ std::map<key, value> or std::unordered_map<key, value>.

assuming staff ids numbers this:

struct staffs {   string username;   string password; }; using staffdirectory = std::map<unsigned long, staffs>;  staffdirectory staff_directory;  // ...  unsigned long id; if (std::cin >> id)  // read id {   // check id   if (!validatestaffid(id))     throw std::runtime_error("invalid staff id: " + to_string(id));   staffs s;   if (std::cin >> s.username >> s.password) // read username , password   {     // add object map, using `id` key     staff_directory[id] = s;   } }