Objective-C Programming: The Big Nerd Ranch Guide

Multiple initializers

Create a new file: a subclass of BNRAppliance named BNROwnedAppliance. In BNROwnedAppliance.h, add a mutable set of owner names and three methods.

#import "BNRAppliance.h"

@interface BNROwnedAppliance : BNRAppliance 
@property (readonly) NSSet *ownerNames;
- (instancetype)initWithProductName:(NSString *)pn
                     firstOwnerName:(NSString *)n;
- (void)addOwnerName:(NSString *)n;
- (void)removeOwnerName:(NSString *)n;

@end

Notice that one of the methods that you have declared is an initializer that takes two arguments.

Implement the methods in BNROwnedAppliance.m:

#import "BNROwnedAppliance.h"

@interface BNROwnedAppliance ()
{
    NSMutableSet *_ownerNames;
}
@end

@implementation BNROwnedAppliance

- (instancetype)initWithProductName:(NSString ...