Class Problem

[Technocrat]

I am not sure how to ask this but here it goes; Lets say I have a class:

class FILE
{
  public:
    std::string sName;
};

Then I use it:

FILE f1;
FILE f2;
f1.sName = "Test.txt";
f2.sName = "Test2.txt";

What I want is to check and make sure this doesnt happen. I want to ensure that each class has a unique sName. So how can I check or ensure this doesnt happen?

[sunburnt]

here's one way
(general outline)

class FILE
{
     private:
       static vector<FILE&> myFILES;
       string sName;

     public:
       FILE()
       {
            myFILES.push_back(*this);       
       };
       ~FILE()
       {
            // remove (*this) from myFILES
       };

        bool SetName(const string &s)
        {
              if ( a FILE exists in the vector with the name s)
                 return false;
              
              sName = s;
              return true;     
        }
};

[Technocrat]

Thanks Sunburnt

I had thought of that I just was wondering if there is an easier and less memory intensive then doing it that way. Seems like there should be a way to access the other classess instances.

Worse case I might just do it that way.

[CornedBee]

There is none, not really. It wouldn't make sense: it would cost large amounts of memory (because the compiler would have to do what sunburnt is doing) and be hardly used.

A way to save some time is to make every class directly a linked list node:

class FILE
{
     private:
       static FILE *pFirst; // Initialize to 0
       FILE *pNext, pPrev;

       string sName;

     public:
       FILE()
       {
              if(pFirst) {
                     pFirst->pPrev = this;
                     pNext = pFirst;
              } else {
                     pNext = 0;
              }
              pPrev = 0;
              pFirst = this;
       };
       ~FILE()
       {
              if(pNext) {
                     pNext->pPrev = pPrev;
              }
              if(pPrev) {
                     pPrev->pNext = pNext;
              } else {
                     pFirst = pNext;
              }
       };

        bool SetName(const string &s)
        {
              if ( a FILE exists in the list with the name s)
                 return false;
              
              sName = s;
              return true;     
        }
};

You can trade construction speed for SetName speed by using a balanced search tree (e.g. std::set) instead of a list. You'd have to write your own sorting predicate though.

[Technocrat]

Yeah to much work for what I am doing. I just figured if there was a way to safely and maybe quickly do it, I would put it in. Thanks everyone.

POST - 900

PS - Thanks Sunburnt for your MP3 script link, its much better than the other one.