Learn OBJECTIVE-C with Real Code Examples

Objective-C extends C with object-oriented features and a dynamic runtime.

It uses a messaging syntax inspired by Smalltalk, allowing flexible method calls and dynamic behavior.

Widely used in legacy iOS/macOS applications, frameworks, and libraries, though Swift is increasingly preferred for new development.

C language foundation with object-oriented extensions

Selectors and dynamic messaging system

Categories for extending existing classes

Protocols for interface definition

Blocks for closures and callback functions

Classes, objects, and methods

Instance and class variables

Message passing using selectors

Protocols and delegates

Memory management (ARC and manual retain/release)

Classes/ - Objective-C class files

Resources/ - images, XIBs, storyboards

Frameworks/ - linked Apple or third-party libraries

Tests/ - unit and UI tests

Supporting Files/ - plist and configuration files

Design class hierarchy and architecture

Write `.h` header and `.m` implementation files

Use Interface Builder for UI design (if applicable)

Compile and link with Apple frameworks

Debug and test on simulator or physical device

Beginner: console-based Objective-C programs

Intermediate: small macOS/iOS apps

Advanced: integrating with Cocoa/Cocoa Touch frameworks

Expert: legacy code maintenance and library development

Enterprise: full-scale commercial Apple applications

More verbose and lower-level than Swift

Provides dynamic runtime not present in Swift

Better for legacy Apple projects

Full C interoperability, unlike Swift in early versions

Declining popularity as Swift adoption grows

Early 1980s – Initial development by Brad Cox and Tom Love

1986 – First commercial implementations

1988 – Objective-C adopted in NeXTSTEP

2000s – Primary language for macOS/iOS development

2025 – Maintained primarily for legacy apps and interoperability

Selector: runtime representation of a method

Category: extends existing class methods

Protocol: defines method contracts

ARC: Automatic Reference Counting

Block: inline closure or callback