HP HP-25 - Editing a Program

Press Display
B 01 15 04 Calculates the arc sine.
Bl 02 15 51 Compares the result to zero.
[0][o] If greater than zero, display arc
sine.
04 03 Otherwise
[6) 05 06 || add
[o] 06 00 360 degrees
07 51 to the arc sine.
To run the program set the PRGM-RUN switch back to RUN
rrov [T~ and pressf [P so that the calculator will be-
gin execution from step 00. Then key in positive or negative
values for x. The resultant arc sine will always be positive.
Press Display
B Set degrees mode.
.5 Arc sine of .5 equals 30 degrees.
.5 Key in negative value for x.
R/S 360 is added to the arc sine to give
a positive angle.
Editing a Program
Even the most experienced programmer finds errors in his pro-
grams. These errors range from mistakes in the original equa-
tions to mistakes in recording the program. Wherever they
occur they need to be found and corrected, and the HP-25 is
designed to make this error-checking process as easy as
possible.
Finding the Error
One of the easiest ways to find out if your program is working
properly is to work a test case in which you either know the
answer or the answer can be easily determined. For example, if
you have a program that calculates the area of a circle using the
formula area = 7 X r2, you can easily determine that an input
value of 1 for r will give an answer of 7.
SST Execution. In longer programs a wrong test-case answer
will seldom pinpoint the mistake. For these cases, you can slow
down
program
execution
by
using
the
3
key
in
RUN
mode.
In RUN mode, the B key will execute your program instruc-