Accessing parent view controller (custom) properties

Question

I have written a UITabBarController subclass (called MainViewController) and added a few instance variables, specifically a venue of type Venue. Ea

Answer 1

int currentVCIndex = [self.navigationController.viewControllers indexOfObject:self.navigationController.topViewController];

//previous view controller
AccountViewController *account = (AccountViewController *)[self.navigationController.viewControllers objectAtIndex:currentVCIndex - 1];

account.property = object;
[account doSmthng];