Objective-C is a general-purpose, object-oriented programming language that adds Smalltalk-style messaging to the C programming language.
This is the main programming language used by Apple for the OS X and iOS operating systems and their respective APIs, Cocoa and Cocoa Touch. This reference will take you through simple and practical approach while learning Objective-C Programming language.
This reference has been prepared for the beginners to help them understand basic to advanced concepts related to Objective-C Programming languages.
Before you start doing practice with various types of examples given in this reference, I'm making an assumption that you are already aware about what is a computer program, and what is a computer programming language?