vector <fstream*> problem

hi, I can't understand how use it:

Code:

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string temp_str;
vector <fstream*> file;
for (int i=0; i < 2; i++) {
  fstream* ff = new fstream;
  *ff << i.toString(); //pseudo-code
    file.push_back(ff);
    ff->close();
}
// now the files are filled with two different strings  ---- MY problem begin here...
vector <fstream*>::iterator fIter; int i;
for (fIter = file.begin(), i=0; fIter != file.end(); ++fIter, i++) {
        (*fIter)->open(computeFileName(i).c_str(), ios_base::in);
        *(fIter[i]) >> temp_str;
          //*(fIter[0]) >> temp_str; //with this, it works! why?
}

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I have 3 files to open and read. In temp_str goes the right string only when i=0; other times when I=1,2 temp_str take nothing. It works all with *(fIter[0]) >> temp_str;
Anyone could explain me how understand this vector??
thanks

because you open the (*fIter) stream, not fIter[i] (which can not exist when the Iterator points to the last item in the vector...

Anyway, if you open file on each iteration, why you need a vector of pointers to streams instead of one temp var of type fstream local for the loop?

hi, I don't understand what your last question mean. could you post your code? thanks

You don't need a vector of fstreams at all. If you close the stream each time, then just use a single fstream variable.

sorry the code is again incomplete...I can have n files (eg 20, 30) and I need to open they 2 at time (then I close two files and go on with other two). I think it's right. probabily I can't keep open many files together.........thanks

The point is that you have a block of code here:

Code:

---

{
  fstream* ff = new fstream;
  *ff << i.toString(); //pseudo-code
    file.push_back(ff);
    ff->close();
}

---

In that block of code, you use the fstream and then close it. Once you've closed the fstream, there is no reason to keep the variable around:

Code:

---

{
  fstream ff;

  // open file and process

  // ff closes automatically
}

---

Then later, just loop over i:

Code:

---

for (int i = 0; i < 2; ++i)
{
  fstream ff;
  ff.open(computeFileName(i).c_str(), ios_base::in);
}

---