flash loop benchmark

Test.as

package
{

import flash.display.Sprite;
import flash.utils.getTimer;

public class Test extends Sprite
{

	private static var a:Array=new Array();
	private static var v:Vector.<int>=new Vector.<int>(1000000);

	private static function testFor():void
	{
		var sum:int=0;
		for(var i:int=0;i<a.length;i++)
			sum+=a[i];

		if(sum!=1783293664)
			throw "fail";		

	}

	private static function testForLocalLength():void
	{
		var len:int=a.length;
		var sum:int=0;
		for(var i:int=0;i<len;i++)
			sum+=a[i];

		if(sum!=1783293664)
			throw "fail";		

	}

	private static function testReversed():void
	{
		var sum:int=0;
		for(var i:int=a.length-1;i>=0;i--)
			sum+=a[i];

		if(sum!=1783293664)
			throw "fail";		

	}

	private static function testForIn():void
	{
		var sum:int=0;
		for(var i:String in a)
			sum+=a[i];

		if(sum!=1783293664)
			throw "fail";		

	}

	private static function testForEachIn():void
	{
		var sum:int=0;
		for each(var i:int in a)
			sum+=i;

		if(sum!=1783293664)
			throw "fail";		

	}

	private static function testVector():void
	{
		var sum:int=0;
		for(var i:int=0;i<v.length;i++)
			sum+=v[i];

		if(sum!=1783293664)
			throw "fail";		

	}

	private static function testVectorReversed():void
	{
		var sum:int=0;
		for(var i:int=v.length-1;i>=0;i--)
			sum+=v[i];

		if(sum!=1783293664)
			throw "fail";		

	}

	private static function testVectorEach():void
	{
		var sum:int=0;
		for each(var i:int in v)
			sum+=i;

		if(sum!=1783293664)
			throw "fail";		

	}

	private static function benchmark(f:Function,text:String):void
	{
		var start:int=getTimer();
		f();
		trace(text,": ",getTimer()-start,"ms");
	}

	public function Test()
	{

		for(var i:int=0;i<1000000;i++)
			a.push(i);

		for(i=0;i<1000000;i++)
			v.push(i);

		benchmark(testFor,"for(var i:int=0;i<a.length;i++)");
		benchmark(testReversed,"for(var i:int=a.length-1;i>=0;i--)");
		benchmark(testForLocalLength,"for(var i:int=0;i<len;i++)");
		benchmark(testForIn,"for(var i:String in a)");
		benchmark(testForEachIn,"for each(var i:int in a)");
		benchmark(testVector,"for(var i:int=0;i<v.length;i++) using Vector");
		benchmark(testVectorReversed,"for(var i:int=v.length-1;i>=0;i--) using Vector");
		benchmark(testVectorEach,"for each(var i:int in v) using Vector");

	}

}

}

well guys, you're fooling yourself here ... a lot.
using for example for(var i:int=0; i < v.length; i++) simply is slower than for(var i:int=v.length-1;i>=0;i--) because there is a request to the .length property of the vector every loop. if you store v.length in a var before the for-loop, you will get the same result as for the "--" version.