How to Go Back to Rootviewcontroller from Presentview Controller

Back to root view controller in swift

You can just set a new RootController like this:

let storyboard = UIStoryboard(name: "sName", bundle: nil)
let viewController = storyboard.instantiateViewController(withIdentifier: "<YOUR ROOT CONTROLLER>")
self.window?.rootViewController = viewController

If you don't have a window at self.window you need to instanciate one based on your AppDelegate.

If you're within a NavigationController you can also use the answer of @Anshul Bhatheja

How to return to Root View Controller

You need to dismiss presented model then you can pop all the pushed view controllers. As presented model would not be in the stack of the navigation.

self.dismissViewControllerAnimated(true, completion: {});

Then you can pop to base view controller.

self.navigationController.popViewControllerAnimated(true);

How to move back to the root view controller in storyboard?

I got the resolution to the issues using the "Unwind Segues".

Step 1) The bare minimum you need is to subclass the view controller for your destination view (aka, a view that has popped up previously in navigation and you want to unwind to it) and add a method like this to it (the method name can be anything you want, but it should be unique because all unwind segues in your entire app are listed together):

- (IBAction)unwindToViewControllerNameHere:(UIStoryboardSegue *)segue {
//nothing goes here
}

Step 2) Now, in your source view (aka, the view that you want to unwind from) you simply drag a segue from your button or whatever down to the little green "EXIT" icon at the bottom of your source view. There should now be an option to connect to "- unwindToViewControllerNameHere"

That's it, your segue will unwind when your button is tapped. And we can move to any view controller we want and rest of the view controllers will be released.

Navigate to root view-controller from modally presented view controller

You can write following inside C

let presenting = self.presentingViewController ?? self.navigationController?.presentingViewController
let navCtrl1 = presenting as? UINavigationController // in case you presented C using b.navigationController.present...
let navCtrl2 = presenting?.navigationController // in case you presented c using b.present...
if let navCtrl = navCtrl1 ?? navCtrl2  {
    self.dismiss(animated: true, completion: {
        navCtrl.popToRootViewController(animated: true)
    })
}

UPDATE

I would like to know if is there anyway to bypass the dismiss and direct pop to root view controller. I want to avoid showing View-controller B

let presenting = self.presentingViewController ?? self.navigationController?.presentingViewController
let navCtrl1 = presenting as? UINavigationController // in case you presented C using b.navigationController.present...
let navCtrl2 = presenting?.navigationController // in case you presented c using b.present...
if let navCtrl = navCtrl1 ?? navCtrl2  {
    navCtrl.popToRootViewController(animated: false)
    self.dismiss(animated: true, completion: nil)
}

How to pop back to root view controller but then push to a different view?

An easy way to accomplish what you want to do is to build some simple logic into your main root view controllers -(void)viewWillAppear method and use a delegate callback to flip the logic switch. basically a "back reference" to the root controller. here is a quick example.

main root controller (consider this controller a) - well call it controllerA
set a property to keep track of the jump status

@property (nonatomic) BOOL jumpNeeded;

setup some logic in

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    self.jumpNeeded ? NSLog(@"jump needed") : NSLog(@"no jump needed");

    if (self.jumpNeeded) {
        NSLog(@"jumping");
        self.jumpNeeded = NO;
        [self performSegueWithIdentifier:@"controllerC" sender:self];
    }   
}

Now, in your main root controller,when a tableview row is selected do something like this
when pushing to controllerB in your tableView did select method

[self performSegueWithIdentifer@"controllerB" sender:self];

then implement your prepare for segue method

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {

  //setup controller B
  if([segue.identifier isEqualTo:@"controllerB"]){
    ControllerB *b = segue.destinationViewController;
    b.delegate = self;  //note this is the back reference
  }

  //implement controller c here if needed
}

Now move on to controllerB
you need to set a property called "delegate" to hold the back reference
and you need to import the header file from the root controller

#import "controllerA"

@property (nonatomic,weak) controllerA *delegate;

then just before you pop back to controllerA, you set the flag

   self.delegate.jumpNeeded = YES;
    [self.navigationController popViewControllerAnimated:YES];

and that is about it. You don't have to do anything with controllerC. There are a few other ways to do, but this is pretty straight forward for your needs. hope it works out for you.