copy使用...自定义类实现copy操作...

#import "Person.h"#import <Foundation/Foundation.h>int main(int argc, const char * argv[]){@autoreleasepool {// 套路: 创建一个类 --> 遵守<NSCopying> --> 实现协议中声明的方法 --> 使用 [对象 copy]Person * p = [[Person alloc] init];p.name = @"项羽";p.age = 25;Person * p1 = [p copy];[p1 description];NSLog(@"address = %p", p);NSLog(@"address = %p", p1);}return 0;}