package 
{
	import by.flastar.utils.Stack;
	import flash.display.Sprite;
	import flash.events.Event;
	
	/**
	 * ...
	 * @author Sergey Gonchar
	 */
	public class StackExample extends Sprite 
	{
		
		public function StackExample():void 
		{
			if (stage) init();
			else addEventListener(Event.ADDED_TO_STAGE, init);
		}
		
		private function init(e:Event = null):void 
		{
			removeEventListener(Event.ADDED_TO_STAGE, init);
			// entry point
			var stc:Stack = new Stack();
			var math:String = "{(x+y-[a+b])*c-[(d+e)]}/(h-(j-(k-[1-n])))";
			var right:Boolean = true;
			newfor:for (var i:int = 0; i < math.length; i++ )
			{
				if (math.charAt(i) == "{" || math.charAt(i) == "[" || math.charAt(i) == "(")
				{
					stc.addItem(math.charAt(i));
				}
				else if (math.charAt(i) == "}")
				{
					if (stc.lastItem == "{")
					{
						stc.removeLastItem();
					}
					else
					{
						right = false;
						break newfor;
					}
				}
				else if (math.charAt(i) == ")")
				{
					if (stc.lastItem == "(")
					{
						stc.removeLastItem();
					}
					else
					{
						right = false;
						break newfor;
					}
				}
				else if (math.charAt(i) == "]")
				{
					if (stc.lastItem == "[")
					{
						stc.removeLastItem();
					}
					else
					{
						right = false;
						break newfor;
					}
				}
			}
			if (right)	Debug.log("Answer true")
			else Debug.log("Answer false");
		}
	}
}