DeepShallow2.swift

class Address
{
    var city: String?
    init(_ city: String?)
    {
        self.city = city
    }
}

var a1 = Address("Mumbai")
var a2 = a1     //This will create a Shallow Copy of a1

print(a1.city)  //Mumbai
print(a2.city)  //Mumbai

a2.city = "Bangalore"

print(a1.city)  //Bangalore
print(a2.city)  //Bangalore