Question

In an .h file, what is the difference between:

@interface ViewController : UIViewController
@property (strong, nonatomic) UIView* myView;

And

@interface ViewController : UIViewController{
    UIView* myView;
}

Answer 1

The main difference is that a @property is visible to other objects, and can be accessed by these using an instance of your class.

You can use @synthesize in your implementation file to automate definition de getter setter functions in your implementation.

Updated (following @Graham Lee‘s suggestion)

According to the visibility specifier for your instance variable (@protected / @private / @public) , the ivar can be used in your implementation file, subclasses or other classes. The implicit value is @protected, so in your example it will be visible to your implementation file and subclasses.