A type can conceptually be viewed as a set of values. If x has the type Real, this means that x belongs to the set of values represented by the type Real.

2
Question

What is a subtype?

2.1

The subtype relation between types is analogous to the subset relation between sets. If a type A1 is a subtype of A, the set of values corresponding to type A1 is a subset of the set of values corresponding to type A.

3
Question

What is a supertype?

3.1

The supertype relation is the inverse of the subtype relation.

4
Subtype and Supertype

Define a class Room that is a Subtype of the class House. Which also means that House is a Supertype of Room. Also give the variables some values.