Designated initializers

GalacticKnight.h

//
//  GalacticKnight.h
//  MoreMessage
//
//  Created by TJ Usiyan on 2016/17/08.
//  Copyright © 2016 Buttons and Lights LLC. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "Person.h"

@interface GalacticKnight : Person {
    NSString *_galaxy;
}

- (instancetype)initWithName:(NSString *)name
                      galaxy:(NSString *)galaxy NS_DESIGNATED_INITIALIZER;


- (NSString *)galaxy;

@end

GalacticKnight.m

//
//  GalacticKnight.m
//  MoreMessage
//
//  Created by TJ Usiyan on 2016/17/08.
//  Copyright © 2016 Buttons and Lights LLC. All rights reserved.
//

#import "GalacticKnight.h"

@implementation GalacticKnight

- (instancetype)initWithName:(NSString *)name
                      galaxy:(NSString *)galaxy {
    self = [super initWithName:name];
    if (self) {
        _galaxy = galaxy;
    }
    return self;
}

- (instancetype)initWithName:(NSString *)name {
    return [self initWithName:name
                       galaxy:@"Unknown"];
}

- (NSString *)galaxy {
    return  _galaxy;
}

@end

main.m

//
//  main.m
//  MoreMessage
//
//  Created by TJ Usiyan on 2016/17/08.
//  Copyright © 2016 Buttons and Lights LLC. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "GalacticKnight.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {

        GalacticKnight *person = [[GalacticKnight alloc] initWithName:@"Elizabeth"
                                                       galaxy:@"Andromeda"];
        NSLog(@"Hi, my name is %@", person);
        NSLog(@"I am from the galaxy %@", [person galaxy]);
    }
    return 0;
}

Person.h

//
//  Person.h
//  MoreMessage
//
//  Created by TJ Usiyan on 2016/17/08.
//  Copyright © 2016 Buttons and Lights LLC. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Person : NSObject {
    NSString *_name;
}

- (instancetype)initWithName:(NSString *)name NS_DESIGNATED_INITIALIZER;
- (NSString *)name;

@end

Person.m

//
//  Person.m
//  MoreMessage
//
//  Created by TJ Usiyan on 2016/17/08.
//  Copyright © 2016 Buttons and Lights LLC. All rights reserved.
//

#import "Person.h"

@implementation Person

- (instancetype)init {
    return [self initWithName:@"Unnamed"];
}

- (instancetype)initWithName:(NSString *)name {
    self = [super init];
    if (self) {
        _name = name;
    }
    return self;
}


- (NSString *)name {
    return _name;
}

- (NSString *)description {
    return _name;
}

@end