"Compound Interest"
By Jess Shadle
ARCADIAN 3 no. 3 (July 9, 1981): 98-99.


Instructions and Background from "Arcadian" newsletter:


Onboard Calculator, ($), has not been utilized fully.  The ARCADIAN tutorial on 
its basic operation was published in Vol. 1, p.32.  At that time, each digit of 
each number had to be individually entered, an arduous task.  Then, in Vol. 2, 
p.2, Gerry Halquist presented a loan payment program with greatly simplified 
input, but still having restrictions (such as interest had to be entered in 5 
digit format).  Now Jess Shadle has made up a number of programs where the 
input format can be almost anything and the program will accept and utilize it.  
One program is included this issue, "Compound Interest."  Some notes:

Entering principal - you can use either $1000 or 1000.00 or 1,000.00; if you do 
not use $, then you must press I after the amount.  Entering interest, any of 
the following will work: 5.2% .052 5.2 but no fractions.  Term of loan must be 
in years.  If you make an error, HALT the program and start again.

If you find this program of value to you in this application or any other, send 
Jess a buck to help keep his creative juices flowing.  He currently is working 
on trig functions, quadratic equation solutions, sinking fund solutions, and 
similar programs - primarily for Blue Ram application.

The capability to do these functions is not included in the AstroVision Basic, 
being removed for other features.  The routine resides in the Bally Basic 
between locations 2194H and 2226H, plus some subroutine calls.  When the VIPER 
system becomes more in use, one could transcribe the routine into the VIPER, 
store the routine on tape, and have it available for when the occasion demands.

For those of you unfamiliar with the calculator format, it is:

$n@(x) ,@(y) ,@(z)

where n is one of the four arithmetic operators:

+, -, x, or the divide sign

@(x) will be the string location of one of the two numbers being worked on, 
while @(y) is the string location of the other.  @(z) is the string location of 
the answer.