Sharp PC-1500 - Page 24

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Now the Gener. al calculates t he actual purchase price at t he PX:
G - (G * . 10) + 8 '' "" "'
0£C RUH
•
and the purcha se price at Discount Bernie's:
G - (G * .05 ) l •NT• •I
Di Ci RUH
.- •• - . ....,. -i- ... t:"
. l
•:i ..::. • .:1 .... t'i ·-'
Clea rl y, Discount Be rn ie's has the better bargain. (Clever readers may have notic ed that the
General could have worked this problem using SHARP's unique rec;i ll fea ture (see Chapter
2), though
not qu ite as easily).
There are
several lessons to be learned from the preceeding exa mple . ..
Observe that the General's first calculation had the following form:
variable.name = expression
An instruction \Vith this form is kn own as an Assignment Statement. It is important not to
confuse an Assignment sta tement with an inequal ity. Unlike Assignm ent statements, inequalities
are not used sepa r .ate ly, but form parts of other progra mm ing ins truct ions .
The Assignment statement instructs SHARP to store the result, obta ined by calculating the
expression, in the memo ry location associated \•Jith the given variable name. Thereafter, using
the name of the variable (G in our example} is just like using the result itself. Notice also that a
1Jariable may be used as many ti mes as needed in th e same calculation.
Variables c;Jn be used for other n eat tric ks , too . Th e val ue of one va riable can he assigned to
another, as in the ·statement:
H = G
which \Viii copy our previo us result into H. G h as not b ee n altered; the same res.1Jlt is no111 stored
in r.vo different variables.
Voriables
wh ict\ hol d nu1nbers can be incremented or decremented in one sta.tement as in this
example:
G = G + 5
This instruction will cause SHARP to recall the value of G, add 5 to that value, and st ore the
new value back into G. This capability is useful for all kinds of calculations:
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