HP HP-28S - User Functions for Unit Conversion

User Functions for Unit Conversion
If you perform particular unit conversions often, you can write user
functions for those conversions. In this section you'll write user func-
tions O-C and C-O that convert between ounces and grams; since
they're user functions, you can use them in either RPN or algebraic
syntax.
Recall
that user functions must fulfill two requirements:
•
They must explicitly indicate their arguments .
•
They must return exactly one result.
First write
O-C.
Begin the program and indicate the argument.
~---------=~~~~~===
0.G ~ x 2: 74.8051948052
1: 'gal'
The right arrow indicates that the following name is a local variable,
which will exist only within this program.
Define the conversion.
o x ['] oz ['] ['] 9 ['] .1 CONVERT I
I
DROP II ENTER I
2: 'gal'
1: « -1- x « x 'oz' , 9 ,
CONVERT DROP » »
mDlIiDIRHlrnHDDDlID
The closing delimiters are added for you.
This
program means: take an argument from the stack (in RPN syn-
tax) or from the expression (in algebraic syntax) and call it x; convert x
from ounces to grams; and drop the gram unit from the stack.
Store
the program in a variable O-C.
~----------------------~
['] o.G G ISTOI 3:
2: 74.8051948052
1 : 'gal'
mDlIiDIRHlrnHDDDlID
14: Unit Conversion 147
I