Q:

How to pop from one view controller to another view controller

Using iOS I Have 15 ViewControllers now I want to pop from one ViewController to another View Controller.
I am using this code:
SecondViewController *Sec=[SecondViewController alloc]init];
[self.navigationController popViewController:Sec animated:YES];

This shows error this ViewController not exist and then I am using this code:
NSArray *array = [self.navigationController viewControllers];
[self.navigationController popToViewController:[array objectAtIndex:1] animated:YES];

This code is right to pop from thirdViewController to secondViewController. But What happened when we pop from Ninth(9th)ViewController to Fifth(5th)ViewController then I am using this code in Ninth(9th)ViewController:
NSArray *array = [self.navigationController viewControllers];
[self.navigationController popToViewController:[array objectAtIndex:4] animated:YES];

It does not pop from Ninth(9th)ViewController to Fifth(5th)ViewController apart that it pops Ninth(9th)ViewController to Eight(8th)ViewController.  I don't know what happened  when we use this line:
NSArray *array = [self.navigationController viewControllers];
NsLog(@"array = %@",array);

When we use this in Ninth(9th)ViewController. NsLog shows:
array=   First(1st)ViewController;  
         Second(2nd)ViewController;
         Eight(8th)ViewController;
         Ninth(9th)ViewController;

I don't know why only Four View Controllers show. Whenever I am using 15 View Controllers.  This problem occurs in each view controller.  For instance if I am Using pop form fifteenth(15th)ViewController to Fifth(5th)ViewController then same problem manifests.
NSArray *array = [self.navigationController viewControllers];
NsLog(@"array = %@",array);

array=     First(1st)ViewController;  
           Second(2nd)ViewController;
           fourteenth(14th)ViewController;
           fifteenth(15th)ViewController;

I want to count Number of ViewControllers and then pop to specific ViewController.

A:

You can't pop to a new view controller (like you do with your secondViewController example).
When using a UINavigationController you
Add Controller to the stack with:
[self.navigationController pushViewController:<yournewViewController> animated:YES];

Pop to the previous one with :
[self.navigationController popViewControllerAnimated:YES];

Pop to a previous controller in the stack (Must have been pushed before) :
[self.navigationController popToViewController:<ViewControllerToPopTo> animated:YES];

Go back to the root Controller with
[self.navigationController popToRootViewControllerAnimated:YES];

A:

for (UIViewController *controller in self.navigationController.viewControllers)
        {
            if ([controller isKindOfClass:[nameOfYourViewControllerYouWantToNavigate class]])
            {
                [self.navigationController popToViewController:controller animated:YES];

                break;
            }
        }

A:

Swift 4.0 - Swift 5.0 
 for controller in self.navigationController!.viewControllers as Array {
            if controller.isKind(of: HomeViewController.self) {
                self.navigationController!.popToViewController(controller, animated: true)
                break
            }
        }

