Selector can either be a name of method or a message to an object when used in the source code. And SEL is the compiled form of a Selector. Also remember that all methods with the same name have the same selector.
iOS Interview Questions with Answers part3
3.What is lazy loading?
Lazy Loading is a programming practice in which you only load or initialize an object when you first need it.
This can potentially give you a big performance boost, especially if you have a lot of components in your application.
What are the differences between Cocoa and Cocoa Touch?
some key concepts for an iPhone developer to learn as a fresher
4. Can we use one Table View with two different Data Sources? How you will achieve this?
A UITableView has something called a dataSource but you seem to be referring, essentially, to two different sets of data.
I would have three arrays.
In the dataSource methods, use the currentlyViewedArray as the source of the table's data.Then, set the currentlyViewedArray to whichever array you want to view:
self.currentlyViewedArray = self.datasetOneArray;
You can use the UISegmentedControl to switch between the two arrays.
What are required delegates and data sources for Table View?
5. What is atomic and non-atomic? Which one is safer? Which one is default??
Atomic guarantees that access to the property will be performed in an atomic manner.
In nonatomic, no such guarantees are made.
Thus, nonatomic is considerably faster than "atomic".
- so "atomic"will be thread safe.
- "atomic" is the default behavior
Where to use atomic in Objective C ?
Why properties are made nonatomic in Objective C?
Best Tutorials- Properties in objective C