c++

The following questions are about the Memento design pattern. 6.1 Both Serializer and Memento design patterns save states of objects and can be used to provide a roll-back facility. When would you use Memento instead of Serializer? 6.2 What objects does Caretaker hold? 6.3 Why is originator a friend of Memento? (2) 6.4 Assume that a state of originator is saved at some stage using the Memento design pattern. State the sequence of actions required to roll back to the saved state of originator. (4)