Introduction to OOP Chapter 12: Implications of substitution: next previous audio real text

An Old Joke Concerning Equality

There is an old joke that goes something like this: A man walks into a pizza parlor and sits down. A waiter comes to the table and asks the man what he would like to order. The man looks around the room, then points to the woman sitting at the next table, and says ``I'll have what she is eating.'' The waiter thereupon walks to the womans table, picks up the half-eaten pizza from in front of her, and places it before the startled customer.

A classic confusion between equality and identity.

Intro OOP, Chapter 12, Slide 16