setter getter 方法

MRC下setter、getter方法写法、重写dealloc方法

@interface People : NSObject 
    @property (nonatomic,strong) NSString *brand; 
    //@property (nonatomic,copy) NSString *brand; 
@end 

setter：
-(void)setBrand:(NSString *)brand{
    //如果实例变量指向的地址和参数指向的地址不同
    if (_brand != brand)
    {
        //将实例变量的引用计数减一
        [_brand release];
        //将参数变量的引用计数加一,并赋值给实例变量
        _brand = [brand retain];
        //copy 使用下列方法
        _brand = [brand copy];
    }
}

getter：
-(NSString *)brand{
    //将实例变量的引用计数加1后,添加自动减1
    //作用,保证调用getter方法取值时可以取到值的同时在完全不需要使用后释放
    return [[_brand retain] autorelease];
}

重写dealloc：
//MRC下 手动释放内存 可重写dealloc但不要调用dealloc 会崩溃
-(void)dealloc{
    [_string release];
    //必须最后调用super dealloc
    [super dealloc];
}

- (void) setCaption: (NSString*)input 
{
    [caption autorelease];
    caption = [input retain]; 
}

- (void) setPhotographer: (NSString*)input
{
    [photographer autorelease];
    photographer = [input retain]; 
}

- (void) dealloc 
{
    [totalAmount release];
    [super dealloc]; 
}