Error in creating subclass in Program 8.7 - ClassB

[todrico]

 
I am getting an error in the interface file for ClassB. It says "Cannot find interface declaration for 'ClassA', superclass of 'ClassB'.  I have gone over and over the examples in the book of program 8.6 and 8.7 to make sure the interface files and implementation files for ClassA and ClassB are correct. I did move the print to ClassA. Need another set of eyes, please!

Code: (Objective-C)

#import <Foundation/Foundation.h>

@interface ClassA : NSObject
{
    int x;
}

-(void) initVar;
-(void) printVar;

@end

[todrico]

Sorry, I punched the post before I was finished pasting my code.  Let me try again. The error occurs at "@interface ClassB: ClassA". Another error occurs in ClassB implementation file when I set "x = 200;" The error I get is "Use of undeclared identifier 'x'". It is probably something simple but I cannot find it.

#import <Foundation/Foundation.h>

@interface ClassA : NSObject
{
    int x;
}

-(void) initVar;
-(void) printVar;

@end

#import "ClassA.h"

@implementation ClassA

-(void) initVar
{
    x = 100;
}

-(void) printVar
{
    printf("x = %i", x);
}
@end

#import <Foundation/Foundation.h>

@interface ClassB: ClassA

-(void) initVar;

@end

#import "ClassB.h"

@implementation ClassB

-(void) initVar
{
    x = 200;
}

@end

[todrico]

I found the solution to my own problem.  When you create the ClassB.h and Class.m files through "File, New File" the window where you declare the subclass, I selected NSObject out of habit.  When I selected "ClassA" for the subclass, everything worked.  However, there was no mention in the book to make sure the proper parent class, ClassA, is selected when creating the files. Being new to Xcode this would have been very helpful a poor assumption on the author's part.