<?php
/* Average - from model #1 (attributes) 
   With schema validation */

function average_1($doc){

//	$start = $doc->lastChild;
    $start = $doc->documentElement;
	
	$k = 0; //number of students/marks
	$s = 0; //total
	$students = $start->getElementsByTagName("student");
	foreach( $students as $student ){ // foreach works with a NodeList !
		$name = $student->getAttribute("name");
		$mark = $student->getAttribute("mark");
		
		echo "$name 's mark is $mark\n";
		$s += $mark;
		$k++;
	}
	if( $k == 0 ){
		die("empty data");
	}else{
		return $s/$k;
	}
}// average_1
	
function reading ($fichIn, $schmFich){
	$doc = new DOMDocument();
	$doc->load($fichIn);
	if( !$doc->schemaValidate($schmFich) ){
  		foreach( libxml_get_errors() as $error ){
     		echo "\t$error->message";
  		}
  		die("Invalid document\n");
	}

	$moy = average_1($doc);
	echo "\nAverage : $moy\n";
}//reading

reading($argv[1], $argv[2]);
?>