Method swizzling is the process of changing the implementation of an existing selector. It's a technique made possible by the fact that method invocations in Objective-C can be changed at runtime, by changing how selectors are mapped to underlying functions in a class's dispatch table.
Apple this year announced two software developments – iOS 8 and OS X and the developer tools that bring them to life which includes a new programming language, Swift. Let us see some numerous features of the iOS8 iPhone and the iPad.
Diagnostics combine logic with analytics to arrive at a conclusion. It's science and engineering at their purest. It's human reasoning at its most potent. For us developers, our medium of code informs the production of subsequent code, creating a positive feedback loop that has catapulted the development of technology exponentially over the last half century. For us Objective-C developers specifically, the most effective diagnostics come from Clang.