AS3中的循环

package cycle
{
	import flash.display.Sprite;
	
	public class CycleTest extends Sprite
	{
		public function CycleTest()
		{
			super();
//			for_cycle();
//			for_in_cycle();
//			for_each_in_cycle();
//			whlie_cycle();
			do_while_cycle();
		}
		
		/**
		 * for循环
		 * 循环前拿到数组的长度可以提高效率
		 * */
		public function for_cycle():void
		{
			var arr:Array = [1,2,3,4,5,6,7];
			var i:int;
			var len:int = arr.length;
			
			for(i=0;i<len;i++)
			{
				trace(arr[i]);
			}
		}
		
		/**
		 * for in循环
		 * 循环可以拿到key value
		 * */
		public function for_in_cycle():void
		{
			var obj:Object = {"x":1 , "y":2};
			
			for(var key:String in obj)
			{
				trace(key + ":" + obj[key]);
			}
		}
		
		/**
		 * for each in循环
		 * 循环可以拿到value
		 * */
		public function for_each_in_cycle():void
		{
			var obj:Object = {"x":1 , "y":2};
			
			for each(var item:int in obj)
			{
				trace(item);
			}
		}
		
		/**
		 * while循环
		 * 满足条件即会运行代码块
		 * */
		public function whlie_cycle():void
		{
			var i:int;
			
			while(i < 5)
			{
				trace(i);
				i++;
			}
		}
		
		/**
		 * do while循环
		 * 不管满不满足条件 都会先运行一遍代码块
		 * */
		public function do_while_cycle():void
		{
			var i:int = 5;
			do{
				trace("do whlile");
			}while(i < 5)
		}
	}
}