How can I make a deep copy in Objective-C?

Question

I\'m learning ios development and I\'m confused with deep copying in Objective-C. For example,I have three class below. Now I want to deep copy ClassA, can anybody teach me

Answer 1

You should add the copyWithZone: method in each class you want to be copiable.

NB: I wrote this by hand, watch out for typos.

-(id) copyWithZone:(NSZone *) zone
{
    ClassA *object = [super copyWithZone:zone];
    object.aInt = self.aInt;
    object.bClass = [self.bClass copyWithZone:zone];
    return object;
}

-(id) copyWithZone:(NSZone *) zone
{
    ClassB *object = [super copyWithZone:zone];
    object.bInt = self.bInt;
    object.cClass = [self.cClass copyWithZone:zone];
    return object;
}

-(id) copyWithZone:(NSZone *) zone
{
    ClassC *object = [super copyWithZone:zone];
    object.cInt = self.cInt;
    object.str = [self.str copy];
    return object;
}