QTextStream out(stdout);

out << trUtf8("Копирование:\n");
double current = 0;
foreach(QString sFileName, all){
    ++current;
    out << "Complete: "
        << ( (current * 100)/cnt) << qSetRealNumberPrecision(3)
        << "%    \r" << flush;
    
    // Делаем полезную работу
}
out << reset << endl << flush;