Detailed graphic and text explanation of how PHP uses text to count visits

$fp = fopen("counter.txt", "r+");
while(!flock($fp, LOCK_EX)) { // acquire an exclusive lock
  // waiting to lock the file
}
$counter = intval(fread($fp, filesize("counter.txt")));
$counter++;
ftruncate($fp, 0);   // truncate file
fwrite($fp, $counter); // set your data
fflush($fp);      // flush output before releasing the lock
flock($fp, LOCK_UN);  // release the lock
fclose($fp);

<?php
/* counter */
//opens countlog.txt to read the number of hits
$datei = fopen("countlog.txt","r");
$count = fgets($datei,1000);
fclose($datei);
$count=$count + 1 ;
echo "$count" ;
echo " hits" ;
echo "\n" ;
// opens countlog.txt to change new hit number
$datei = fopen("countlog.txt","w");
fwrite($datei, $count);
fclose($datei);
?>

<?php
include("counter.php");
?>