10+ FADD Studio Interview Questions and Answers

Classes and structures are both used to define custom data types, but they have some key differences.

• Classes are reference types, while structures are value types.

• Classes support inheritance, while structures do not.

• Classes have deinitializers, while structures do not.

• Classes have reference counting for memory management, while structures do not.

• Classes can have optional property types, while structures cannot.

Retain cycle is a memory management issue where objects reference each other and cannot be released. It can be avoided by using weak or unowned references.

• Retain cycle occurs when two or more objects hold strong references to each other.

• To avoid retain cycle, use weak or unowned references instead of strong references.

• Weak references do not increase the reference count of an object and automatically become nil when the object is deallocated.

• Unowned references are similar to w...read more

A closure is a self-contained block of code that can be passed around and used in your code. An escaping closure is a closure that is called after the function it was passed to has returned.

• Closure is a block of code that can be passed around and used in your code.

• Escaping closure is called after the function it was passed to has returned.

• Example: Using a completion handler in a network request to handle the response after the request has finished.

GCD and Operation Queues are both used for concurrent programming in iOS, but differ in their approach.

• GCD is a C-based API that uses a thread pool model for concurrency.

• Operation Queues are built on top of GCD and provide a higher-level abstraction for concurrency.

• GCD is best for simple, lightweight tasks, while Operation Queues are better for more complex tasks with dependencies.

• GCD uses blocks for task execution, while Operation Queues use Operation objects.

• GCD has a lower...read more

The life cycle of iOS applications refers to the stages an app goes through from launch to termination.

• The app is launched by the user or system

• The app enters the foreground and becomes active

• The app can be sent to the background or suspended

• The app can be terminated by the user or system

• The app can be resumed from the background or suspended state

• The app can receive memory warnings and handle them appropriately

The UIViewController life cycle consists of several stages that occur when the view controller is loaded and unloaded.

• viewDidLoad() - called when the view controller's view is loaded into memory

• viewWillAppear() - called just before the view appears on the screen

• viewDidAppear() - called just after the view appears on the screen

• viewWillDisappear() - called just before the view disappears from the screen

• viewDidDisappear() - called just after the view disappears from the screen

• de...read more

Use a Set to get distinct members in array while maintaining sequence.

• Iterate through the array and add each element to a Set to automatically remove duplicates.

• Create a new array by iterating through the Set to maintain the original sequence.

Opinion binding is a legal doctrine that requires judges to follow the decisions of higher courts in similar cases.

• Opinion binding is also known as stare decisis.

• It helps to ensure consistency and predictability in the legal system.

• For example, if a higher court has already ruled that a certain law is unconstitutional, lower courts must follow that ruling in similar cases.

• Opinion binding can be controversial, as it can prevent judges from correcting past mistakes or adapting ...read more

Multi threading is the ability of a CPU to execute multiple threads concurrently, allowing for improved performance and responsiveness in applications.

• Allows for parallel execution of tasks, improving performance

• Enables applications to remain responsive while performing intensive tasks

• Can lead to synchronization issues if not managed properly

let is used for constants that do not change, var is used for variables that can change

• let is used for constants that do not change

• var is used for variables that can change

• let variables cannot be reassigned once they are set

• var variables can be reassigned multiple times

Operation queue is a way to manage and execute tasks asynchronously in iOS applications.

• Operation queue allows you to add tasks (operations) to a queue and execute them in the background.

• It provides control over the execution of tasks, such as setting dependencies between tasks.

• Operations can be added to the queue with different priorities, allowing for better task management.

• Example: NSOperationQueue is a class in iOS that represents an operation queue.