PHP XML Expat Parser

<?php
// Initialize the XML parser
$parser = xml_parser_create();

// Function to use at the start of an element
function start($parser, $element_name, $element_attrs) {
  switch($element_name) {
    case "NOTE":
    echo "-- Note --<br>";
    break;
    case "TO":
    echo "To: ";
    break;
    case "FROM":
    echo "From: ";
    break;
    case "HEADING":
    echo "Heading: ";
    break;
    case "BODY":
    echo "Message: ";
  }
}

// Function to use at the end of an element
function stop($parser, $element_name) {
  echo "<br>";
}

// Function to use when finding character data
function char($parser, $data) {
  echo $data;
}

// Specify element handler
xml_set_element_handler($parser,"start","stop");

// Specify data handler
xml_set_character_data_handler($parser,"char");

// Open XML file
$fp = fopen("note.xml","r");

// Read data
while ($data = fread($fp,4096)) {
  xml_parse($parser,$data,feof($fp)) or
  die (sprintf("XML Error: %s at line %d",
  xml_error_string(xml_get_error_code($parser)),
  xml_get_current_line_number($parser)));
}

// Free the XML parser
xml_parser_free($parser);
?>