snprintf (fmt, sizeof(fmt), "%%-%ds", col - i);
snprintf (fmt, sizeof(fmt), "%%-%ds", i - col);
static int pad (FILE *f, int col, int i){  char fmt[8];  if (i < col)  {    snprintf (fmt, sizeof(fmt), "%%-%ds", col - i);    fprintf (f, fmt, "");    i = col;  }  else  {    fputc (' ', f);    ++i;  }  return (i);}