выборка группы файлов для записи на носитель, предполагается что пару батников вы запустили

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include "rx.h"

using namespace std;

class File
{
public:
 string FileName;
 int Size;
        File(string Name, int Sz) : FileName(Name), Size(Sz) {}
};

vector<File> Group;
randomx g(time(NULL));

void read_db()
{
        ifstream f("Files.LST");
        char buf[1250];
 while (f.good())
 {
  int Sz;
  string Name, Full_name;
  char Name_buf[512];
  f >> Sz;
  f.get(Name_buf, 255, '\n');
  Full_name = "C:\\Aleksandr\\Files\\";
                Full_name += Name_buf+1;
  Group.push_back(File(Full_name, Sz));
 }
}

void save_sequence()
{
#define TOTAL_EXPECTED 4482
 int Total_files = Group.size();
 int Expected_size_Mb = 0;
 while (Expected_size_Mb < TOTAL_EXPECTED)
 {
  int Next_file = g.rand_n(Total_files);
  string command("");
  command += "copy \"";
  command += Group[Next_file].FileName;
  command += "\">nul";
  system(command.c_str());
  double added_size = Group[Next_file].Size;
                added_size /= 1024;
                added_size /= 1024;
                Expected_size_Mb += (int)added_size;
                string polzunok("");
                double vsego_blokov;
                double percents;
                percents = Expected_size_Mb;
                percents /= TOTAL_EXPECTED;
                percents *= 100;
                vsego_blokov = 80;
                vsego_blokov /= 100;
                vsego_blokov *= percents;
                for (int i=0; i<(int)vsego_blokov; i++)
                 polzunok += "#";
                printf("\r%s", polzunok.c_str());
 }
}

int main()
{
    read_db();
    save_sequence();
    return 1;
}