HP Prime Graphing Wireless Calculator - Manual (Page 258)

254 Programming in HP PPL
Program ROLLDIE We’ll first create a program called ROLLDIE. It simulates
the rolling of a single die, returning a random integer
between 1 and whatever number is passed into the
function.
In the Program Catalog create a new program named
ROLLDIE. (For help, see page 241.) Then enter the code
in the Program Editor.
EXPORT ROLLDIE(N)
BEGIN
RETURN 1+RANDINT(N-1);
END;
The first line is the heading of the function. Execution of the
RETURN statement causes a random integer from 1 to N
to be calculated and returned as the result of the function.
Note that the RETURN command causes the execution of
the function to terminate. Thus any statements between the
RETURN statement and END are ignored.
In Home view (in fact, anywhere in the calculator where a
number can be used), you can enter ROLLDIE(6) and a
random integer between 1 and 6 inclusive will be
returned.
Program
ROLLMANY
Because of the EXPORT command in ROLLDIE, another
program could use the ROLLDIE function and generate n rolls
of a die with any number of sides. In the following program,
the ROLLDIE function is used to generate n rolls of two dice,
each with the number of sides given by the local variable
sides. The results are stored in list L2, so that L2(1) shows
the number of times the dies came up with a combined total
of 1, L2(2) shows the number of times the dies came up with
a combined total of 2, etc. L2(1) should be 0 (since the sum
of the numbers on 2 dice must be at least 2).
EXPORT ROLLMANY(n,sides)
BEGIN
LOCAL k,roll;
// initialize list of frequencies
MAKELIST(0,X,1,2*sides,1) ▶ L2;
FOR k FROM 1 TO n DO
ROLLDIE(sides)+ROLLDIE(sides) ▶ roll;