AppDelegate.cpp显示未定义标识符HelloWorldLayer

#ifndef __helloworld__HelloWorldLayer__

#define __helloworld__HelloWorldLayer__

#include<iostream>

#include"cocos2d.h"

USING_NS_CC;

class HelloWorldLayer :public Layer

{

public:

static HelloWorldLayer * create();

virtual bool init();

};

#endif

以上是HelloWorldLayer.h