How to get the previous viewcontroller that pushed my current view

Question

The home page of my app has UIButtons, btnIncome and btnExpense. Pressing on this buttons pushes IncomeVC and Expen

Answer 1

In Swift 3,

if let navController = self.navigationController, navController.viewControllers.count >= 2 {
     let viewController = navController.viewControllers[navController.viewControllers.count - 2]
}