1.1. Introducing the iOS development tools

Objective-C is a strict superset of the procedural-based C programming language. This fact means that any valid C program is also a valid Objective-C program (albeit one that doesn’t make use of any Objective-C enhancements).

Objective-C extends C by providing object-oriented features. The object-oriented programming model is based on sending messages to objects, which is different from the model used by C++ and Java, which call methods directly on an object. This difference is subtle but is also one of the defining features that enables many of Objective-C’s features that are typically more at home in a dynamic language such as Ruby or Python.