HP (Hewlett-Packard) HP 33s Calculator User Manual


 
Simple Programming
12–3
File name 33s-English-Manual-040130-Publication(Edition 2).doc Page : 388
Printed Date : 2004/1/30 Size : 13.7 x 21.2 cm
Designing a Program
The following topics show what instructions you can put in a program. What you
put in a program affects how it appears when you view it and how it works when
you run it.
Selecting a Mode
Programs created and saved in RPN mode can only be edited and executed in
RPN mode, and programs or steps created and saved in ALG mode can only be
edited and executed in ALG mode. You can ensure that your program executes in
the correct mode by making RPN or ALG the first instruction in the program.
Program Boundaries (LBL and RTN)
If you want more than one program stored in program memory, then a program
needs a
label to mark its beginning (such as


) and a return to mark
its end (such as


).
Notice that the line numbers acquire an
to match their label.
Program Labels
Programs and segments of programs (called routines) should start with a label. To
record a label, press:
¹
Ó
letter–key
The label is a single letter from A through Z. The letter keys are used as they are for
variables (as discussed in chapter 3). You cannot assign the same label more than
once (this causes the message

), but a label can use the same
letter that a variable uses.
It is possible to have one program (the top one) in memory without any label.
However, adjacent programs need a label between them to keep them distinct.
Program Returns
Programs and subroutines should end with a return instruction. The keystrokes are:
º
Ô