Pop to specific ViewController in NavigationController

gistfile1.m

// Navigation Stack -> (pushed)
// Steps 1. AViewController -> 2. BViewController -> 3. CViewController
// in the CViewController user tapped button -> -backToFirstViewController

// backToFirstViewController

- (void)backToFirstViewController {
    // get navigation stack as an array.
    NSArray *viewControllers = self.navigationController.viewControllers;
    
    // First way
    // This way array goes back twice and find AViewController. This is obvious.
    [self.navigationController popToViewController:viewControllers[viewControllers.count-2] animated:YES];
    
    // Second way
    for(UIViewController *currentVC in viewControllers) {
        if([currentVC isKindOfClass:[AViewController class]]) {
            [self.navigationController popToViewController:currentVC animated:YES];
        }
    }
}