How to sort multidimensional array

// Script : How to sort multidimensional array

<?php

	$students = array (
		256 => array ('name' => 'Jon', 'grade' => 98.5),
		2 => array ('name' => 'Vance', 'grade' => 85.1),
		9 => array ('name' => 'Stephen', 'grade' => 94.0),
		364 => array ('name' => 'Steve',  'grade' => 85.1),
		68 => array ('name' => 'Rob', 'grade' => 74.6),
		56 => array ('name' => 'Ed', 'grade' => 88.6),
		365 => array ('name' => 'Samantha', 'grade' => 92.5),
		424 => array ('name' => 'John', 'grade' => 96.0)
	);




	function name_sort($x , $y)
	{
		static $count = 1;
		echo "<p>Iteration $count : $x[name] vs $y[name] </p>\n";
		$count++;
		return strcasecmp($x['name'], $y['name']);
	}

	function grade_sort($x , $y)
	{
		static $count = 1;
		echo "<p>Iteration $count : $x[grade] vs $y[grade] </p>\n";
		$count++;
		return $x['grade'] < $y['grade'];
	}

	var_dump("Array is" , $students);

	usort($students, 'name_sort');

	var_dump("Array sorted by name" , $students);

	usort($students, 'grade_sort');

	var_dump("Array sorted by grade" , $students);

 ?>