108 Chapter Four
How variables are local to processes and subprograms and are
used mainly as scratch pad areas for local calculations.How constants name a particular value of a type.How integers behave like mathematical integers, and real numbers
behave like mathematical real numbers.How enumerated types can be used to describe user-defined
operations and make a model much more readable.How physical types represent physical quantities such as distance,
current, time, and so on.The composite type, arrays and records. Arrays are a group of
elements of the same type, and records are a group of elements of
any type(s).How access types are like pointers in typical programming
languages.How file types are linear streams of data of a particular type that
can be read and written from a model.How subtypes can add constraints to a type.In the next chapter, we focus on another method of sequential statement
modeling: the subprogram.