xcode: following tutorial but 'subViewOneController' undeclared error

So I'm new to programming for the iPhone and开发者_开发知识库 I'm trying this new tutorial here: http://theappleblog.com/2009/04/15/iphone-dev-sessions-create-a-navigation-based-application/

When I build the project, under the: RootViewController.m

I get a 'subViewOneController' undeclared error at the first line:

// allocate a set of views and add to our view array as a dictionary item

SubViewOneController *subViewOneController = [[SubViewOneController alloc] init];

subViewOneController.title = @"Subview One";

What does the error mean? and where should I look to make sure names are matching?

Thanks, Matt

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You need to make sure that a class called SubViewOneController exists, and that you're importing its header (SubViewOneController.h) in RootViewController.m