Radio Shack TRS-80 Model 100 Basic Manual page 157

Line
68
Execution jumps back to line 20 to create another coin toss.
Execute and use (BREAK) to terminate the program several times. Notice that the
program generates exactly the same outcome every time. This is a characteristic of
RND(l). Every time a program is run, the same sequence of random numbers will be
generated. While this is convenient when you are debugging your program, it does not
provide the unpredictability characteristic of true randomness. What is required is a
way of starting the sequence of random numbers at an arbitrary point.
Add the following line to the program:
15 A=RND(-VAL(RIGHT$(TIME$t2»)
List the program to verify that it is:
10 CLS
15 A = RND(-VAL(RIGHT$(TIME$t2»)
2121 A
=
RND (
1)
3121 IF A(.5 THEN A$="HEAD" ELSE A$="TAIL"
al2l PR I NT A$, "PRESS ENTER
II
5121 A$ = INKEY$ : IF A$ = "" GOTO 5121
6121 GOTO 2121
Execute the program several times to verify that different sequences of outcomes are
being generated each time.
Remember to use
~
to terminate execution.
The RND function can be used with three types of arguments:
x RND(x)
greater than 0
equal to 0
less than 0
generates next random number
generates same random number
generates a new sequence of
random numbers dependent
upon the value of x
In this program, the time is used
to
determine the sequence of random numbers by
negating the seconds of the current time. This will provide 60 different sequences of
random numbers. Recall that the time is stored as a string in TIME$ and must be
converted to a numeric value using the VAL function.
Experiment #8 Slot machine
This experiment will combine sound, animation and random numbers in one program
to simulate a slot machine.
Enter the following program:
1121 A=RND(-VAL(RIGHT$(TIME$t2»)
2121 CLS
3121 LINE (85t12) - (138,53)t1,6
a0
LINE (88,22) -
(110t33)
t1 t6
5121 LINE -(122,22) t1 ,6
6121 LINE -(13a,33)t1,6
151