Objective-C small sample codes

main.m

#import "Foundation/Foundation.h"
#import "User.h"

int main(void) {
  User *foo = [[User alloc] init];
  foo.name = @"Komamitsu";
  foo.age = 123;
  NSLog(@"%@", [foo hello:@"Bye"]);
  return 0;
}

User.h

#import "Foundation/Foundation.h"

@interface User : NSObject
- (NSString*)hello:(NSString*)msg;

@property(copy) NSString *name;
@property int age;
@end

User.m

#import "User.h"

@implementation User

@synthesize age;
@synthesize name;

- (NSString*)hello:(NSString*)msg {
    return [NSString stringWithFormat: @"Hello, my name is %@. %@\n", self.name, msg];
}
@end

$ clang -Wall -lobjc -framework Foundation -fobjc-gc-only main.m User.m