classes.m

#import <Foundation/Foundation.h>

// ============================
// MyClass
// ============================

@class YourClass;

@interface MyClass : NSObject
{
  float myFloat;
  YourClass *friend;
}

- (void) hello;

@end

@implementation MyClass

- (id) init
{
  self = [super init];
  if(self != nil)
  {
    myFloat = 5.0;
  }
  return self;
}

- (void) hello
{
  NSLog(@"Hello, I'm your first Objective-C program!");
}

- (void) dealloc
{
  // release any retained objects here.
  [super dealloc];
}

@end

// ============================
// YourClass
// ============================

@interface YourClass : NSObject
{
  // no variables
}

- (NSString *) goodbye;

@end

@implementation YourClass

- (id) init
{
  self = [super init];
  if(self != nil)
  {
    // No variables
  }
  return self;
}

- (NSString *) goodbye
{
  return @"Goodbye, nice seeing you!";
}

- (void) dealloc
{
  // release any retained objects here.
  [super dealloc];
}

@end

// ============================
// main
// ============================

int main(int argc, char**argv)
{
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

  // allocate an instance
  MyClass *instance = [[MyClass alloc] init];
  [instance hello];

  [pool release];

  return 0;
}