Normally I would put private methods in the header file. But noticed from "Learn Cocos2D 2nd Edition" book a different way been used.The header file is quite simple:#import "cocos2d.h"@interface HelloWorld : CCLayer{}// returns a Scene that contains the HelloWorld as the only child+(id) scene;@endThe private methods are however declared in the .m file as shown below with "(PrivateMethods)" added behind "@interface":#import "HelloWorldScene.h"// private methods are declared in this manner to avoid "may not respond to ..." compiler warnings@interface HelloWorld (PrivateMethods)-(void) onCallFunc;-(void)...