@interface Person : NSObject
{
    NSString *_name;
}
@property (copy) NSString *name;
@end

@implementation Person
@synthesize name=_name;
@end

我不明白和下面这样写有何区别？

@interface Person : NSObject
{
    NSString *name;
}
@property (copy) NSString *name;
@end

@implementation Person
@synthesize name;
@end