Highly related to the previous keywords, the ! is used to tell the compiler that I know definitely, this variable/constant contains a value and please use it (i.e. please unwrap the optional). From question 1, the block that executes the if condition is true and calls a forced unwrapping of the optional's value. There is a method for avoiding forced unwrapping which we will cover below.
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In the context of an NSOperation object, which runs in an NSOperationQueue, the terms concurrent and non-concurrent do not necessarily refe...
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This borrows very much from C/C++. It allows you to alias a type, which can be useful in many particular contexts. typealias AudioSample ...
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Retain counts are the way in which memory is managed in Objective-C. When you create an object, it has a retain count of 1. When you send a...