Sharp PC-1500A Instruction Manual page 24

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Now the General calculates the actual purchase p rice at the PX:
G - (G* .10 )
+
8
IENTEAI
DCC
RUM
I •
l
1
:
1
.:::
C1C1~
1_11_1 •
!"_. ·-· - ·
and the purchase price at Discount Bernie's:
G - (G* .05) l•HT••I
DCC
RUN
•
Clearly, Discount Oer1'lie's has the better barga in. (Clever readers may have noticed that the
General could have worked this problem using SHARP's unique recall featu re (see Chapter
2), though not Quite as easily) .
There are severa I lessons to be learned from the preceed ing example . . .
Observe that the General's first calcu lation had the following fo rm:
variable-name
=
expression
An instruction w ith this form is known as an Assignment Statement. It is important not to
confuse an Assignment statement with an inequality. Unlike Assignment statements, inequalities
are not used separately, but form parts of other programming instructions.
The Assignment statement instructs SHARP to store the result, obtained by calculating the
expression, in the memory location associated w : i th the given variable name. T hereafter, using
the name of the variable (G in our example) is juot like using the result itself. Notice also that a
variable may be used as many times as needed in the same calculation.
Variables can be used fo r other neat tricks, too. The value of one variable can be assigned to
another. as in the statement:
H = G
which will copy our previous result into H.
G
has not been altered; the same result is now stored
in two (iifferent variables.
Variables which hold numbers can be incremented or decremented in one statement as in this
example:
G
=
G + S
This instruction will cause SHARP to recall the value of G, add 5 to that value, and store the
new value back into G. This capability is useful for all kinds of calculations:
2·2
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