Objective-C

Description #

Objective-C is a compiled, object-oriented programming language that adds Smalltalk-style messaging to the C programming language. It was the primary language used for macOS and iOS development before the introduction of Swift.

History #

Objective-C was created in the early 1980s by Brad Cox and Tom Love at Stepstone as an extension of the C language with object-oriented capabilities. It became widely known when NeXT (founded by Steve Jobs) adopted it for its operating system. Apple later acquired NeXT, bringing Objective-C to macOS and iOS. It remained the dominant Apple development language until Swift was introduced in 2014.

Hello World Code #

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSLog(@"Hello, World!");
    }
    return 0;
}

How to Run #

Option 1: Online

• OnlineGDB – Objective-C

Option 2: Local (macOS)

Open Terminal

Save code as hello.m

Compile and run:

clang -framework Foundation hello.m -o hello
./hello

Key Concepts #

1. Based on C with object-oriented extensions
2. Uses message-passing syntax ([object message])
3. Dynamic runtime like Smalltalk
4. Foundation and Cocoa frameworks
5. Automatic Reference Counting (ARC)
6. Categories and protocols
7. Header (.h) and implementation (.m) files
8. Interoperable with Swift and C
9. Still supported by Apple in Xcode
10. Known for verbose but flexible syntax

Try It Online #

• OnlineGDB – Objective-C

Fun Facts #

• Apple’s early apps, including iTunes and Safari, were built using Objective-C.
• Steve Jobs helped popularize Objective-C via NeXT, which later became the foundation for macOS and iOS.
• Swift was designed to interoperate seamlessly with Objective-C.

Resources #

• Apple Objective-C Guide
• Objective-C on Rosetta Code
• GNUstep – Open-source Objective-C
• Online Compiler – OnlineGDB