fetching coredata in objective c - objective-c

Question

I've been trying to learn Objective C and been following a tutorial teaching using CoreData.
I have made a viewcontroller with a cancel and save button, the tutorial provides the code, however after copying and pasting the code, I get errors.
Could it be that this tutorial i'm following is several years old, and in some way this code is outdated?
The error are from "NSManagedObject *newDevice...." to "if (![context save:&error])"
This is my code:
#import "DeviceDetailViewController.h"
#interface DeviceDetailViewController ()
#end
#implementation DeviceDetailViewController
- (NSManagedObjectContext *)managedObjectContext {
NSManagedObjectContext *context = nil;
id delegate = [[UIApplication sharedApplication] delegate];
if ([delegate performSelector:#selector(managedObjectContext)]) {
context = [delegate managedObjectContext];
}
return context;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
- (IBAction)cancell:(id)sender {
[self dismissViewControllerAnimated:YES completion:nil];
}
- (IBAction)save:(id)sender {
NSManagedObjectContext *context = [self managedObjectContext];
// Create a new managed object
NSManagedObject *newDevice = [NSEntityDescription insertNewObjectForEntityForName:#"Device" inManagedObjectContext:context];
[newDevice setValue:self.nameTextField.text forKey:#"name"];
[newDevice setValue:self.versionTextField.text forKey:#"version"];
[newDevice setValue:self.companyTextField.text forKey:#"company"];
NSError *error = nil;
// Save the object to persistent store
if (![context save:&error]) {
NSLog(#"Can't Save! %# %#", error, [error localizedDescription]);
}
[self dismissViewControllerAnimated:YES completion:nil];
}
#end

Answer 1

It looks like you haven't imported the Core Data framework header file. You need a line at the top of the file reading
#import <CoreData/CoreData.h>