How to perform a Objective-C deep copy [duplicate]

Question

This question already has answers here:

How can I make a deep copy in Objective-C? (6 answers)

Closed 9 years ago.

Does the Objective-c copy method do a deep copy of an object?

NSObject *clone = [self copy];

Answer 1

NSObject *clone = [self copy];

Wont perform deep copy but would be a shallow copy.

You need to implement NSCopying protocol like this

//ContactCard.h
@interface ContactCard : NSObject<NSCopying>
{
    NSString* name;
    NSString* email;
}
...
-(id)copyWithZone:(NSZone *)zone;
@end

//ContactCard.m
@implementation ContactCard
...
-(id)copyWithZone:(NSZone *)zone
{
    ContactCard* cc = [[ContactCard allocWithZone:zone]init];
    cc->email = [email copy];
    cc->name = [name copy];
    return cc;
}
...
@end

You can read more on enter link description here Or refer Apple docs on NSCopying

Answer 2

this might be help. For deep copy of any custom object we need to adopt NSCopying protocol in that class. How to copy an object in objective c