不完全深拷贝要实现完全深拷贝

需求：默认状态下深拷贝指的是不完全深拷贝, 如要实现完全深拷贝, 则要重写copyWithZone: 方法, 自行实现完全深拷贝的
实现：大体思路如下, 在copyWithZone: 里对象赋值上不直接赋值而是通过copy方法即可实现

// Person.m
- (id)copyWithZone:(NSZone *)zone
{
    Person *cpyPerson = [[Person allocWithZone:zone] init];
    cpyPerson.name = self.name;
    cpyPerson.age = self.age;
    return cpyPerson;
}
// NSArray
- (id)copy
{
    NSArray *cpyArray = [[NSArray alloc] initWithArray:self copyItems:YES];
    return cpyArray;
}
// main.m
Person *p1 = [[Person alloc] init];
Person *p2 = [[Person alloc] init];
NSArray *array = @[p1, p2];
NSArray *cpyArray = [array copy];
NSLog(@"%@ - %@", array, cpyArray);
// 输出结果
(
    "<Person: 0x100204af0>",
    "<Person: 0x100206b20>"
) - (
    "<Person: 0x100207910>",
    "<Person: 0x1002074d0>"
)