<?

// Read in data from a file
$content = getData("data.txt");
// Split data up wherever there is a comma
$vals = split(",",$content);

// two variables
$x = $vals[0];
$dir = $vals[1];

// Increment x
$x += $dir;

// Reverse dir if x hits an "edge"
if ($x > 5 || $x <= 0){
  $dir *= -1;
}

// Write out new values to file
writeData("data.txt","$x,$dir");

// Print some stuff to browser
for($i = 0; $i < $x; $i++){
  echo "&nbsp;"; // A space
}

echo "X";

// Function to write to file
function writeData($filename,$content){
  $dest = fopen("$filename", 'w') ;
  fwrite($dest,$content);
  fclose($dest);
}

// Function to read from file
function getData($filename){
  $size = filesize($filename);
  if ($size == 0) return array(0,1);
  $src = fopen($filename, 'r');
  $content = fread($src,$size);
  fclose($src);
  return $content;
}
?>