HP 49g+, Руководство пользователя, Страница: 666 / 862

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,
) 1 2 ( 3 2
4
2
2
S S S
S
⋅ ⋅ ⋅
which indicates the position of the different stack input levels in the formula.
By comparing this result with the original formula that we programmed, i.e.,
,
) ( 2
2
2
by g
Q
h
v
=
we find that we must enter y in stack level 1 (S1), b in stack level 2 (S2), g in
stack level 3 (S3), and Q in stack level 4 (S4).
Prompt with an input string
These two approaches for identifying the order of the input data are not very
efficient. You can, however, help the user identify the variables to be used by
prompting him or her with the name of the variables. From the various
methods provided by the User RPL language, the simplest is to use an input
string and the function INPUT (
„°L @)@@IN@@ @INPUT@
) to load your input
data.
The following program prompts the user for the value of a variable a and
places the input in stack level 1:
«
“ Enter a: “ { “ :a: “ {2 0} V } INPUT OBJ →
»
This program includes the symbol :: (tag) and
(return), available through the
keystroke combinations
„ê
and
‚ë
, both associated with the
.
key. The tag symbol (::) is used to label strings for input and output. The
return symbol (
) is similar to a carriage return in a computer. The strings
between quotes (“ “) are typed directly from the alphanumeric keyboard.
Save the program in a variable called INPTa (for INPuT a).
Try running the program by pressing the soft menu key labeled
@INPTa
.