DeepShallow4.swift

class Person: NSObject, NSCopying
{
    var name: String?
    var address: Address?
    
    init(_ name: String?, _ address: Address?)
    {
        self.name = name
        self.address = address
    }
    
    func copy(with zone: NSZone? = nil) -> Any
    {
        let person = Person.init(self.name, self.address)
        return person
    }
}

var a1 = Address("Mumbai")

var p1 = Person("John", a1)
var p2 = p1.copy() as! Person //This will create a Deep Copy of p1

print("Name: \(p1.name), City: \(p1.address?.city)")  //Name: John, City: Mumbai
print("Name: \(p2.name), City: \(p2.address?.city)")  //Name: John, City: Mumbai

p2.name = "Stefen"
p2.address?.city = "Bangalore"

print("Name: \(p1.name), City: \(p1.address?.city)")  //Name: John, City: Bangalore
print("Name: \(p2.name), City: \(p2.address?.city)")  //Name: Stefan, City: Bangalore