ARC対応（？）のHello World

これでなんとか動いて今のところエラーや警告が出てないのです
リソースファイルはiOS Developer CenterにあるsampleのHello Worldから
お借りして使ってます。
ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController {

    IBOutlet UITextField* textFiled;
    IBOutlet UILabel* label;
    NSString* string;
    
}
@end

ViewController.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController {

    
    
}    
- (void)viewDidLoad
{
    textFiled.clearButtonMode = UITextFieldViewModeWhileEditing;
    label.text = textFiled.placeholder;
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
}

-(void)updateSring {
    string =textFiled.text;
    
    label.text = string;
}

- (BOOL)textFieldShouldReturn:(UITextField *)theTextField {
    if (theTextField == textFiled) {
        [textFiled resignFirstResponder];
        [self updateSring];
    }
    return YES;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    [textFiled resignFirstResponder];
    textFiled.text = string;
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

@end