Renaming Files the Hard Way

[whitewolf]

I am trying to write a program that will rename files to an organizational standard. For example, MP3s will be renamed to "track number" SPACE "track title." My approach to this problem is that I would copy every single byte of information in the file and then put them into the new, correctly named file. I will delete the original and implement a way to rename multiple files later on in development. Anyway, here's the code:

#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    ifstream fin("C:\\Documents\\Programming\\Files\\07_luciano.pavarotti_miserere.mp3");
    ofstream fout("C:\\Documents\\Programming\\Files\\07 Miserere.mp3");

    char ch;
    while(!fin.eof())
    {
        fin.get(ch);
        fout.put(ch);
    }

    fin.close();
    fout.close();

    return 0;
}

The issue here is that I am not copying every byte and I think it's because the eof marking may appear at random times during the MP3 file. So then I tried some little snippet of code I found here on c++.com:

pbuf = fin.rdbuf();
size = pbuf->pubseekoff(0,ios_base::end);
pbuf->pubseekpos(0,ios::in);

char ch;
while(size != 0)
{
    fin.get(ch);
    fout.put(ch);
    size--;
}

This produces gobbledygook that looks like the ID3 tags and then a repeated character when output to a text file. So my question is how do I rename a file in this fashion? Is there an easier way? I may be way over complicating things lol. I would like to stay away from using

char oldname[] = "oldname.txt";
char newname[] = "newname.txt";

rename(oldname, newname);

because then I have to declare the size of the array and filepaths aren't one specific size.

[Lamblion]

Instead of going through that entire ream of hassles, why don't you just use the rename() function?

[whitewolf]

I took your suggestion and did some digging around here and eventually ended up with a way to do this.

    string oldn;
    string newn;
    oldn = "C:\\Documents\\Programming\\Files\\07-luciano_pavarotti--miserere-_with_zucchero.mp3";
    newn = "C:\\Documents\\Programming\\Files\\07 Miserere.mp3";

    char *cstr1, *cstr2;    //declaration of character string eventually pointing to the location where oldn and newn are stored

    cstr1 = new char [oldn.size()+1];    //allocate memory to hold oldn and newn PLUS the null terminated character
    strcpy(cstr1, oldn.c_str());    //copy to cstr1 the contents of oldn. Note oldn.c_str() is the same as oldn only c_str points to a null terminated character array.

    cstr2 = new char [newn.size()+1];
    strcpy(cstr2, newn.c_str());

    cout << cstr1 << endl << endl;    //checking to see what cstr1 and 2 hold
    cout << cstr2 << endl << endl;

    rename(cstr1, cstr2);    //renaming

    delete []cstr1;
    delete []cstr2;

It would still be interesting to see what the bits were in the MP3 but in terms of renaming things, its solved.

[chrisname]

What is the point of

    string oldn;
    string newn;
    oldn = "C:\\Documents\\Programming\\Files\\07-luciano_pavarotti--miserere-_with_zucchero.mp3";
    newn = "C:\\Documents\\Programming\\Files\\07 Miserere.mp3";

Why not just

string oldn("foo"),
       newn("bar");

Also,

   char *cstr1, *cstr2;    //declaration of character string eventually pointing to the location where oldn and newn are stored

    cstr1 = new char [oldn.size()+1];    //allocate memory to hold oldn and newn PLUS the null terminated character
    strcpy(cstr1, oldn.c_str());    //copy to cstr1 the contents of oldn. Note oldn.c_str() is the same as oldn only c_str points to a null terminated character array.

    cstr2 = new char [newn.size()+1];
    strcpy(cstr2, newn.c_str());

    cout << cstr1 << endl << endl;    //checking to see what cstr1 and 2 hold
    cout << cstr2 << endl << endl;

    rename(cstr1, cstr2);    //renaming

    delete []cstr1;
    delete []cstr2;

Could just be

cout << oldn << "\n\n"
     << newn << "\n" << endl;

rename(oldn.c_str(), newn.c_str());

[whitewolf]

cout << oldn << "\n\n"
     << newn << "\n" << endl;

rename(oldn.c_str(), newn.c_str());

Huh, didn't realize that lol. That is nice and simple. Thanks you!