Question

This code is a portion of a FTP client that I have developed:

  for(size_to_receive = file_size; size_to_receive > 0;){
    nread = read(f_sockd, filebuffer, size_to_receive);
    if(nread < 0){
      perror("read error on retr");
      close(fd);
      return -1;
    }
    if(write(fd, filebuffer, nread) != nread){
      perror("write error on retr");
      close(fd);
      return -1;
    }
    size_to_receive -= nread;
  }

I would like to implement the percentage of the downloaded file but I have some problems. I’ve tried with this method:

  for(size_to_receive = file_size; size_to_receive > 0;){
    nread = read(f_sockd, filebuffer, size_to_receive);
    tx += nread;
    printf("%d%%\n", (tx * 100 / file_size));
    fflush(NULL);
    if(nread < 0){
      perror("read error on retr");
      close(fd);
      return -1;
    }
    if(write(fd, filebuffer, nread) != nread){
      perror("write error on retr");
      close(fd);
      return -1;
    }
    size_to_receive -= nread;
  }

but I don’t like it because when the transfer starts, “20%” is immediately printed and also because if I remove the \n from 20%%\n – 40%%\n etc., the values are printed at the end of the transfer and not immediately.

How can I develop better code?

Answer 1

for (size_to_receive = file_size; size_to_receive > 0;) {
    nread = read(f_sockd, filebuffer, size_to_receive);
    tmp_xc += nread;

    printf("%d%%\r", (tmp_xc * 100 / file_size));
    fflush(NULL);
}