Filter
Top Products
Programming in HP PPL 513
Note that EXPORT
command for the
variable RADIUS
appears before the
heading of the function
where RADIUS is
assigned. After you
execute this program, a
new variable named RADIUS appears on the USER
GETRADIUS section of the Variables menu.
Qualifying
the name of a
variable
The HP Prime has many system variables with names that
are apparently the same. For example, the Function app
has a variable named Xmin, but so too does the Polar
app, the Parametric app, the Sequence app, and the
Solve app. In a program, and in the Home view, you can
refer to a particular version of these variables by
qualifying its name. This is done by entering the name of
the app (or program) that the variable belongs to,
followed by a dot (.), and then the actual variable name.
For example, the qualified variable Function.Xmin
refers to the value of Xmin within the Function app.
Similarly, the qualified variable Parametric.Xmin
refers to the value of Xmin in the Parametric app. Despite
having the same name—Xmin—the variables could have
different values. You do likewise to use a local variable in
a program: specify the name of the program, followed by
the dot, and then the variable name.
Functions,
their
arguments,
and
parameters
You can define your own functions in a program, and data
can be passed to a function using parameters. Functions
can return a value (using the RETURN statement) or not.
When a program is executed from Home view, the
program will return the value returned by the last statement
that was executed.
Furthermore, functions can be defined in a program and
exported for use by other programs, in much the same
way that variables can be defined and used elsewhere.
In this section, we will create a small set of programs, each
illustrating some aspect of programming in the HP Prime.
Each program will be used as a building block for a
custom app described in the next section, App Programs.