IBM Senior IOS Developer Interview Questions and Answers

App Life Cycle refers to the sequence of events that occur from the time an app is launched until it is terminated.

• App is launched by user or system

• App enters foreground and becomes active

• App enters background when user switches to another app or locks the device

• App may be terminated by the system to free up resources

• App can be brought back to foreground by user or system events

Extension of enum allows adding new cases, computed properties, and methods to an existing enum type.

• Extensions can be used to add new functionality to existing enum types without modifying their original implementation.

• New cases, computed properties, and methods can be added to an enum using extensions.

• Extensions can also be used to conform an enum to a protocol.

Delegate methods of URL session are used to handle various events during network requests.

• Delegate methods are used to handle authentication challenges, background session events, and data tasks.

• Examples include URLSessionDelegate, URLSessionDataDelegate, URLSessionTaskDelegate.

• Delegate methods can be used to handle redirects, caching policies, and response validation.

SSL pinning is a security measure used to prevent man-in-the-middle attacks by validating the server's SSL certificate.

• Implement SSL pinning by embedding the server's SSL certificate within the app's code.

• During the SSL handshake, compare the server's certificate with the embedded certificate to ensure they match.

• If the certificates match, the connection is considered secure and the data exchange can proceed.

• SSL pinnin...read more

Classes are reference types, structs are value types. GCD is low-level API, Operation queue is high-level API for concurrency.

• Classes are reference types, stored on the heap. Structs are value types, stored on the stack.

• GCD is a low-level API for managing concurrent operations. Operation queue is a high-level API built on top of GCD.

• GCD provides a simple and efficient API for dispatching tasks to a queue. Operation que...read more

SOLID principles are a set of five design principles that help make software designs more understandable, flexible, and maintainable.

• Single Responsibility Principle (SRP) - A class should have only one reason to change.

• Open/Closed Principle (OCP) - Software entities should be open for extension but closed for modification.

• Liskov Substitution Principle (LSP) - Objects of a superclass should be replaceable with objects o...read more