What happens when the following code executes?

Ball *ball = [[[[Ball alloc] init] autorelease] autorelease];

Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the (...) programming language

While calling a function by reference, it will copy the actual value of an argument into the formal parameter of the function. In this case, changes made to the parameter inside the function have no effect on the argument. Is the statement above True ?

Which method creates and returns an NSNumber object containing a given value, treating it as an NSInteger.

Which one is the base class of all objects in Objective-c ?

The description above is essentially related to which feature of Objective-C programming language ?

What happens at runtime with the following: NSMutableString *tempString = [NSMutableString stringWithString:@"1"]; dispatch_sync(dispatch_get_main_queue(), ^{ [tempString appendString:@"2"]; NSLog(@"%@", tempString); }); [tempString appendString:@"3"];

A UIView is a superclass of:

Which of these methods is NOT invoked by the runtime itself?

How is a selector typically represented in memory?

What's the difference between nil and NULL?