I have written a function to write data in a doc file,

public function createDoc($dir) {
        if ($_REQUEST) {            
            header("Content-type: application/vnd.ms-word");
            header("Content-Disposition: attachment;Filename = MyDoc.doc");
            $all_txt_files = glob($dir.'/*.txt');
            foreach ($all_txt_files as $file) {
                $fileParts = explode('/', $file);
                $this->outputContent .= "<h1>".$fileParts[count($fileParts) - 1]."</h1><p>".file_get_contents($file)."</p>";
                echo "<h1>".$fileParts[count($fileParts) - 1]."</h1><p>".file_get_contents($file)."</p>";
            }
        }
        return $this->outputContent;
    }

but, after returning from this function still, each echo statement write in the same file, how to prevent that?