What is a type?
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.
What is a subtype?
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.
What is a supertype?
The supertype relation is the inverse of the subtype relation.
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.