# **🍏 Booth: Objective-C (1984)** * **Creator:** Brad Cox and Tom Love * **Design Philosophy:** Objective-C was created as a thin, clean OOP extension to the standard C programming language. It fused the procedural performance of C with the clean, highly dynamic message-passing model of Smalltalk. * **Key Innovations:** Dynamic runtime system, selector-based message dispatch, category extensions (appending methods without subclassing), and dynamic typing (id). ## **🚀 Hello, World\!** \#import \ int main(int argc, const char \* argv\[\]) { @autoreleasepool { NSLog(@"Hello, World\!"); } return 0; } ## **🎨 Showpiece: Custom Class and Message Sending** In Objective-C, method calling is fundamentally treated as message passing. The syntax \[receiver message\] does not resolve statically; instead, it is handled at runtime via the Objective-C messaging system: ![][image1]\#import \ // \--- Interface Declaration \--- @interface GreetingMachine : NSObject { NSString \*\_prefix; } \- (instancetype)initWithPrefix:(NSString \*)prefix; \- (void)greetUser:(NSString \*)name; @end // \--- Implementation \--- @implementation GreetingMachine \- (instancetype)initWithPrefix:(NSString \*)prefix { self \= \[super init\]; if (self) { \_prefix \= \[prefix copy\]; } return self; } \- (void)greetUser:(NSString \*)name { NSLog(@"%@, %@\!", \_prefix, name); } @end // \--- Execution \--- int main(int argc, const char \* argv\[\]) { @autoreleasepool { // Instantiate and send keyword-style messages GreetingMachine \*greeter \= \[\[GreetingMachine alloc\] initWithPrefix:@"Welcome to the Museum"\]; \[greeter greetUser:@"Ada Lovelace"\]; } return 0; } [image1]: