MRC下set和get方法的重写

@interface List : NSObject
{
    NSString *_name;
}
-(void)setName:(NSString *)name;
-(NSString *)name;
@end 

@implementation List
-(void)setName:(NSString *)name
{
    if (_name!=name) {
    [_name release];
    _name=[name retain];
    }
}
-(NSString *)name
{
    return _name;
}
@end