Objective-C

Hello World

Xcode, Interface Builder und Co. are very powerful tools, but sometimes they seem to make things a little bit more complicated than they really are. Here's a short program in Objective-C:

#import <Foundation/Foundation.h>
 
int main (int argc, const char * argv[]) {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    
	// Hello World!
	printf("About to print the most important message...\n");
	NSLog(@"Hello World!\n");
	
    [pool release];
    return 0;
}

You can compile either with a simple Editor that supports this (e.g. TextMate: Actions: Run) - or you use the gcc compiler with Bash (Terminal.app):

cd ~/Path/to/HelloWorld.m
gcc HelloWorld.m -o HelloWorld -framework Foundation
./HelloWorld

Objective-C Introduction

• en.wikipedia.org/wiki/Objective-C - very good, because short & intrinsic Overview
• Objective-C - official Apple Docs on Objective-C

Objective-C versus ...

• Comparison Chart between ObjC, C++, Java, Ruby, Smalltalk, ...

NeXTStep

Cocoa and Objective-C kind of belong to each other. Usually you'll hear that Objective-C is only useful on Mac OS and bound to Apple Stuff only, but this is not true: While NeXTStep originated over 20 years ago, there's also GNUstep which aims to bring Cocoa to all major OS (*nix & Windows):

• GNUstep.org
  • GNUstep on Wikipedia
  • History of NeXtStep

Basically GNUstep's Project Center is like Xcode and Gorm is like Interface Builder.

...btw, that's where all the NS-Prefixes come from (NeXTStep), eg in NSObject, NSArray, ...

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Diese Seite ist Teil des Werkmoduls iOS Development von Michael Markert für Interface Design / Fakultät Medien an der Bauhaus-Universität Weimar.