after calling an func for init the UIAlertController remains nil - objective-c

Question

I have 2 alerts I want to present in different cases, I wrote a general function to init the alerts in the beginning and change the messages later, but when I am trying to present the alert I get a crash. When I inspect the notesAlert in runtime it is still nil.
Can someone explain what I did wrong?
#interface viewController (){
UIAlertController *tableAlert;
UIAlertController *notesAlert;
}
#end
#implementation viewController
- (void)viewDidLoad {
[super viewDidLoad];
[self initAlert:tableAlert];
[self initAlert:notesAlert];
}
// func to init the alerts
-(void)initAlert:(UIAlertController*)alert{
alert = [UIAlertController alertControllerWithTitle: #"" message: #"" preferredStyle:UIAlertControllerStyleActionSheet];
[alert setModalPresentationStyle:UIModalPresentationPopover];
[alert.popoverPresentationController setSourceView:self.view];
UIPopoverPresentationController *popover = [alert popoverPresentationController];
CGRect popoverFrame = CGRectMake(0,0, self.view.frame.size.width/2, self.view.frame.size.width/2);
popover.sourceRect = popoverFrame;
UIAlertAction *dismiss = [UIAlertAction actionWithTitle:#"Ok" style:UIAlertActionStyleDefault handler:nil];
[alert addAction:dismiss];
}
- (IBAction)showNotes:(id)sender {
// here the notesAlert is still nil
[notesAlert setTitle:#"oops"];
[notesAlert setMessage:#"you pressed the wrong one"];
[self presentViewController:notesAlert animated:YES completion:nil];
}
#end

Answer 1

[self initAlert: notesAlert]; doesn't create notesAlert. Instead, you could use notesAlert = [self initAlert];
Maybe something like this:
#interface ViewController () {
UIAlertController *tableAlert;
UIAlertController *notesAlert;
}
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.tableAlert = [self initAlert];
self.notesAlert = [self initAlert];
}
// func to init the alerts
- (UIAlertController *) initAlert {
UIAlertController *alert = [UIAlertController alertControllerWithTitle: #"" message: #"" preferredStyle: UIAlertControllerStyleActionSheet];
[alert setModalPresentationStyle:UIModalPresentationPopover];
[alert.popoverPresentationController setSourceView: self.view];
UIPopoverPresentationController *popover = [alert popoverPresentationController];
CGRect popoverFrame = CGRectMake(0,0, self.view.frame.size.width/2, self.view.frame.size.width/2);
popover.sourceRect = popoverFrame;
UIAlertAction *dismiss = [UIAlertAction actionWithTitle: #"Ok" style: UIAlertActionStyleDefault handler:nil];
[alert addAction: dismiss];
return alert;
}