Implementation file can't see Constant declared in header file - objective-c

Question

I am getting error messages in the implementation file (commented out) for Constants declared in the header file. Why is the compiler doing this?
Thanks in advance.
Header file:
#import <UIKit/UIKit.h>
#define kFilling Component 0
#define kBread Component 1
#interface BIDDoubleComponentViewController : UIViewController
<UIPickerViewDelegate, UIPickerViewDataSource>
#property (strong, nonatomic) IBOutlet UIPickerView *doublePicker;
#property (strong, nonatomic) NSArray *fillingTypes;
#property (strong, nonatomic) NSArray *breadTypes;
- (IBAction) buttonPressed;
#end
Implementation file:
#import "BIDDoubleComponentViewController.h"
#implementation BIDDoubleComponentViewController
- (IBAction)buttonPressed
{
NSInteger fillingRow = [self.doublePicker selectedRowInComponent:kFillingComponent]; // Use of undeclared identifieer 'kFillingComponent'
NSInteger breadRow = [self.doublePicker selectedRowInComponent:kBreadComponent]; // Use of undeclared identifieer 'kBreadComponent'
NSString *filling = self.fillingTypes[fillingRow];
NSString *bread = self.breadTypes[breadRow];
NSString *message = [[NSString alloc] initWithFormat:#"Your %# on %# will be right up.", filling, bread];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Thank you for your order"
message:message
delegate:nil
cancelButtonTitle:#"Great"
otherButtonTitles:nil];
[alert show];
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
self.fillingTypes = #[#"Ham", #"Turkey", #"Peanut Butter", #"Tuna salad", #"Chicken salad", #"Roast Beef", #"Vegemite"];
self.breadTypes = #[#"White", #"Whole Wheat", #"Rye", #"Sour Dough", #"Seven-Grain"];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark
#pragma mark Picker Data Source Methods
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 2;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
if(component == kBreadComponent) // Use of undeclared identifieer 'kFillingComponent'
{
return [self.breadTypes count];
} else {
return [self.fillingTypes count];
}
}
#pragma mark Picker Delegate Methods
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
if(component == kBreadComponent) // Use of undeclared identifieer 'kBreadComponent'
{
return self.breadTypes[row];
} else {
return self.fillingTypes[row];
}
}
#end

Answer 1

Your defines are bad. You have
#define kBread Component 1
But you're using kBreadComponent. What the #define is doing is it's defining a token called kBread that evaluates during preprocessing to the tokens Component 1. You probably meant to use
#define kBreadComponent 1