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Need help/advice on system

Heres what I need to do:

I need to implement a system for storing strings, and I need to be able to easily add and remove strings from it as fast and efficently as posssible. Also each string will have an associated id (unsigned long), and I need to be able to find a string by its id aswell. I can't use databases, so it all has to be done with files.

I hope Im explaining this well. Basically the interface would consist of 4 functions:

Code:

void AddString(string)

void RemoveString(id)

string findStringById(id)

id findIdByString(string)

Im having problems figuring out how the data would be organised. Any advise would be appreciated

Are you aware of UNIX db api ? Try man db, just to see
It can works with flat-file format

If you are using C++ and want to stay standard and portable, I'd suggest std::map and std::string, then make a wrapper class for the map:

Code:

//Off the top of my head; compiled, but not linked or run

#include <string>

#include <map>



class StringData

{

public:

        typedef unsigned long      id;

        typedef std::string        data;

        typedef std::map <id, data> storage;



                void

        AddString(data dData, id iId) //<- need to give the id also

        { MapData.insert( MapData.end(), storage::value_type(iId, dData) ); }



                void

        RemoveString(id iId)

        { MapData.erase(iId); }



                data

        findStringById(id iId)

        { return MapData[iId]; }



                id

        findIdByString(data sString)

        {

        //This isn't like normal iteration because of no < or - operators

        storage::iterator DataPoint = MapData.begin();

        id Curr = 0;



        while (Curr < MapData.size())

        {

        if (DataPoint->second == sString) return DataPoint->first;



        else

          {

        DataPoint++;

        Curr++;

          }

        }



        return 0; //Default return

        }



private:

                storage

        MapData;

};

It was easier to just write something than try to explain what I meant. This isn't perfect, unless I got really lucky, but hopefully this gives you some ideas. If you go this route, you should wrap the size function and some of the other basic map functions. Take a look here:
http://www.sgi.com/tech/stl/table_of_contents.html
ta0kira

PS I just realized you might be talking about a file, therefore you could use the above plus an interface class to read/write the file. That I'm not sure about though.

thanks, ta0kira, I'll look into that route