HP HP-28S User Manual

User Functions. The programs COT, PSUM, O .... G, and G .... O are
user
functions-they begin with the command .... and one or more
names, which together define
one or more local variables, followed by
one expression or program. When the user function is stored in a vari-
able, you can use
the name of the variable in algebraics as you would
use a built-in function.
Program Structures. The command .... followed by names and an
expression or program is called a local-variable structure, which is one
type of program structure. There are also program structures for
branching (such as
IF ... THEN ... ELSE ... END) and looping (such
as
DO ... UNTIL ... END). See chapter 26, uProgram Structures," for
descriptions. Also,
chapter 28, uProgramming Examples," contains 20
programs
that demonstrate every program structure, along with a va-
riety of programming techniques.
Unnamed Programs. Programs don't need to be stored in variables
to be useful; for examples, see HExpanding
and Collecting Com-
pletely,"
on page 253, and HDisplaying a Binary Integer," on page 257.
Aigebraics
Algebraics comprise one or more functions and the functions' argu-
ments;
the arguments can be numbers, names, or subexpressions.
Algebraics are written
and displayed in algebraic syntax, a form simi-
lar to written mathematical notation. There are two types of
algebraics, expressions
and equations.
Expressions
In part 1 you used expressions in three different ways: as data, as
functions,
and as implicit equations.
Expressions As Data. When you calculate with expressions, such as
adding two expressions, squaring an expression, or differentiating an
expression, the result is another expression. In these cases the expres-
sions act as
data to be manipulated, independent of any values
assigned to the variables.
16: Objects 161
I

HP HP-28S Specifications

General

Introduced	1988
Memory	32 KB
Number of Digits	12
Type	Scientific Calculator
Manufacturer	Hewlett-Packard (HP)
Display	LCD
Processor	Saturn
Programming	RPL

Summary

HP-28S Advanced Scientific Calculator Owner's Manual

Part 1: Fundamentals

Introduces basic operations, calculator features, and core concepts.

Getting Started

Covers initial setup, basic operations, and calculator overview.

Doing Arithmetic

Explains methods for performing calculations using stack and expressions.

Part 2: Summary of Calculator Features

Objects

Describes fundamental data types, symbolic operations, and programming elements.

The Command Line

Explains input methods, cursor control, and command entry.

The Stack

Reviews stack concepts and commands for manipulating objects.

Part 3: Programming

Program Structures

Covers conditional logic, loops, and error handling in programs.

Conditional Structures

Explains testing conditions and making decisions within programs.

Definite Loop Structures

Details structures for executing code a specific number of times.

Appendixes & Indexes

Appendix A: Assistance, Batteries, and Service

Provides troubleshooting, battery info, and service details.

Answers to Common Questions

Addresses frequent user queries and common calculator issues.

Appendix B: Notes for HP RPN Calculator Users

Highlights differences for users familiar with RPN calculators.

Appendix D: Menu Map

Lists commands by menu, with descriptions and page references.

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