如何让一个类能被copy修饰

//

//  Person.h

//  tst

//

//  Created by zmx on 16/2/17.

//  Copyright © 2016年 zmx. All rights reserved.

//

#import <Foundation/Foundation.h>

@interface Person : NSObject <NSCopying>

@property (nonatomic, copy) NSString *name;

@end

//

//  Person.m

//  tst

//

//  Created by zmx on 16/2/17.

//  Copyright © 2016年 zmx. All rights reserved.

//

#import "Person.h"

@implementation Person

- (id)copyWithZone:(NSZone *)zone {

    Person *person = [Person allocWithZone:zone];

    person.name = self.name;

    return person;

}

@end