Xcode runtime error: ".objc_class_name_CContext", referenced from:

I'm getting this error in Xcode while developing an app for iPhone , what is this error related to, ... what should i do to clear this error? Here CContext and CManager are interface which implement there own protocols.And TestManagerAppDelegate is the interface where i'm creating the object for CContext and CManager and i want to call the methods using there own objects.

ERROR:

".objc_class_name_CContext", referenced from:
".objc_class_name_CManager", referenced from:
collect2:id retirned 1 exit status
literal-pointer@_OBJC@_cls_refs@CContext in TestManagerAppDelegate.o
li开发者_开发知识库teral-pointer@_OBJC@_cls_refs@Cmanager in TestManagerAppDelegate.o
symbol(s) not found

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It looks like the files that contain the implementations for the CContext and CManager classes (probably CContext.m and CManager.m) were not included in your Xcode project.