บทนำสู่ Objective-C

Objective-C shaped the early days of iOS and macOS. Swift is newer, but Objective-C still powers a huge base of existing enterprise apps.

Born in the early 1980s and adopted by NeXT, Objective-C became Apple's primary language for macOS and iOS after the 1997 acquisition.

Objective-C is a superset of C: plain C runs inside it, and it layers object-orientation and message passing on top. Powerful, if tricky at first.

Objective-C is object-oriented, but you do not call methods — you send messages to objects with the bracket syntax [object method:arg].

Objective-C has a powerful dynamic runtime: method dispatch is decided at run time, enabling tricks like swizzling and introspection.

Why learn it today? Millions of lines of Objective-C still run shipping apps. You need it to maintain legacy code and migrate to Swift.

Your first program. Note the @autoreleasepool for memory and NSLog, which prints like printf but for Objective-C objects.

Breaking it down: #import pulls in Foundation, main is the entry point, @autoreleasepool manages memory, and NSLog prints.

Behind the scenes Xcode runs four steps to your program: preprocess, compile, link, and run. It handles all of it for you.

Based on what we've learned, consider Objective-C's relationship with the C language.

Recap: Objective-C is a superset of C with OOP, a dynamic runtime, and deep legacy importance — and you ran your first NSLog program.