Objective-C. Program not from the book

First time something that was not in the book:

#import <Foundation/Foundation.h>

@interface Dot: NSObject
{
    int x;
    int y;
}

@property int x, y;

@end;

@implementation Dot

@synthesize x, y;

@end

@interface Something : NSObject
{
    int capacity;
    Dot** array;
}

@property int capacity;
@property (nonatomic, assign) Dot** array;

- (Something*) init;
- (Something*) initWithCapacity : (int)n;
- (BOOL) isEmpty;
- (void) dealloc;

@end

@implementation Something

@synthesize array;
@synthesize capacity;

- (Something*) init
{
    array = Nil;
    capacity = 0;
    return self;
}

-(Something*) initWithCapacity : (int)n
{
    int i;
    self = [super init];
    array = (Dot**)malloc(n * sizeof(Dot*));
    for (i = 0; i < n; ++i)
    {
        array[i] = [[Dot alloc] init];
        array[i].x = i;
        array[i].y = i * i;
    }
    capacity = n;
    return self;
}

- (BOOL)isEmpty
{
    return capacity == 0;
}

- (void) dealloc
{
    int i;
    for (i = 0; i < capacity; ++i)
    {
        [array[i] release];
    }
    free(array);
    [super dealloc];
}

@end


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

    Something* something = [[Something alloc] initWithCapacity: 10];

    int i;
    for (i = 0; i <  something.capacity; ++i)
    {
        NSLog(@"array[%i] = %i, %i", i, something.array[i].x, something.array[i].y); 
    }
        
    [something release];
    
    Something* test = [[Something alloc] init];
    if (![test isEmpty])
        test.array[0].x = 1;
    [test release];
    [pool drain];
    return 0;
}