Undeclared Identifier for UI fields in custom function

Question

I created a custom function shown below with code I copied from a button click event in my .m file. The code worked fine until I copied it into my displayDev function. The last three lines in this code give me a "Use of undeclared identifier" error. Can someone help me figure out why fullVerseLabel.text, VerseField.text, and InterpretationField.text are all displaying as undeclared identifiers? Also below is my .h code where I declared these UI fields.

Any help you can provide will be greatly appreciated. Thanks so much!

void displayDev (NSInteger dayNum)
{   NSString *plistFile = [[NSBundle mainBundle] pathForResource:@"Property List" ofType:@"plist"];
    NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:plistFile];

    NSString *bookString = [[dict objectForKey:[NSString stringWithFormat:@"Day %d", dayNum]] objectForKey:@"Book"];
    NSString *chapterString = [[dict objectForKey:[NSString stringWithFormat:@"Day %d", dayNum]] objectForKey:@"Chapter#"];
    NSString *verseString = [[dict objectForKey:[NSString stringWithFormat:@"Day %d", dayNum]] objectForKey:@"Verse#"];

    NSString *fullVerseString = [bookString stringByAppendingString:@" "];
    fullVerseString = [fullVerseString stringByAppendingString:chapterString];
    fullVerseString = [fullVerseString stringByAppendingString:@":"];
    fullVerseString = [fullVerseString stringByAppendingString:verseString];
    fullVerseLabel.text = fullVerseString;
    VerseField.text = [dict objectForKey:[NSString stringWithFormat:@"Day %d", dayNum]objectForKey:@"Verse"];
    InterpretationField.text = [dict objectForKey:[NSString stringWithFormat:@"Day %d", dayNum] objectForKey:@"Interpretation"];

    currentlyViewing = dayNum;
}

I have the variables declared in my .h file and linked to my storyboard.

@interface FirstViewController : UIViewController
{   IBOutlet UILabel *fullVerseLabel;
    IBOutlet UITextView *VerseField;
    IBOutlet UITextView *InterpretationField;
    IBOutlet UITextField *TextField;
}

Answer 1

You started this method with:

void displayDev (NSInteger dayNum)

With that syntax, you're actually declaring this as a C function, not Objective-C. You're unable to access your outlets or other instance variables in a C function. You can change it to an Objective-C instance method by changing the first line to:

- (void)displayDev:(NSInteger)dayNum