Langage c: déplacement dans un répertoire

SYNOPSIS
       #include <sys/types.h>

       #include <dirent.h>

       struct dirent *readdir(DIR *dir);

DESCRIPTION
       The readdir() function returns a pointer to a dirent structure representing the next
       directory entry in the directory stream pointed to  by  dir.   It  returns  NULL  on
       reaching the end-of-file or if an error occurred.

       On Linux, the dirent structure is defined as follows:

         struct dirent {
             ino_t          d_ino;       /* inode number */
             off_t          d_off;       /* offset to the next dirent */
             unsigned short d_reclen;    /* length of this record */
             unsigned char  d_type;      /* type of file */
             char           d_name[256]; /* filename */
         };

       According  to POSIX, the dirent structure contains a field char d_name[] of unspeci-
       fied size, with at most NAME_MAX characters preceding the terminating  null  charac-
       ter.   POSIX  1003.1-2001  also documents the field ino_t d_ino as an XSI extension.
       Use of other fields will harm the portability of your programs.

       The data returned by readdir() may be overwritten by subsequent calls  to  readdir()
       for the same directory stream.

RETURN VALUE
       The  readdir() function returns a pointer to a dirent structure, or NULL if an error
       occurs or end-of-file is reached.  On error, errno is set appropriately.

#include <iostream>
using namespace std;

void sablier(unsigned int compteur,unsigned int max){
    unsigned int i,largeur_char=80;
    static unsigned int progression=0;

    //Dessin de la barre de progression
    cout.flush();
    cout << "("<<compteur<<"/"<<max<<")";
    if (max==0 || compteur>max || ((largeur_char*compteur)/max<=progression) ){
        cout << "\r";
        return;
    }
    cout << "[";
    for(i=0;i<(largeur_char*compteur)/max;i++) cout << "=";
    progression=i;
    if (i<largeur_char) cout << ">";
    for(;i<largeur_char-1;i++) cout << " ";
    cout << "]\r";

    //Barre remplie
    if (compteur==max){
        cout << endl;
        progression=0;
    }
}