How to read/write a file?

How to read/write a file? I have a directory call “tempd” on my server. Directory is set to 777. Inside directory I have two files “readfile.php” and “writefile.php”. They both are 777 as well. I copy a template in my theme folder and call it “testtemplate.php”. In this new template I have the following code but it is not working. Any help would be greatly appreciated.

<?php
$handle = fopen('http://www.example.com/tmpd/readfile.php','r');
$data = fread($handle, filesize($handle));
fclose($handle);
$handle1 = fopen('http://www.example.com/tmpd/writefile.php','w');
$newdata = 'My name is '.$data;
fwrite($handle1,$newdata);
fclose($handle1);