Experiment
#7
How to Escape From
an
Infinite
Loop
It is easy to add some statements so that programs that contain infinite loops will
terminate upon request.
In the Sales Commission program, for example, the sales total will never
be
negative.
But you can modify the program so that it terminates whenever a negative value for
sales is entered.
Type the
new
line:
15
IF
ST
< 0
THEN
STOP
(ENTER)
The
STOP
statement, terminates execution and has the same effect as pressing
~.
The program will terminate
if
ST
is negative, but continue
if
it is not.
Run the program.
When prompted to do so, enter a dummy name (such as END) and a negative sales
amount (such as
-1).
Note that the program terminates immediately without
computing any commission.
The dummy name was necessary because the INPUT statement in Line 10 requires
you to enter two input quantities. Since a negative sales amount terminates execution,
the name you enter will not be used.
You can have more than one
STOP
statement in your program.
Of
course your
program need not have any STOP statements in it at all.
Experiment
#8
Individual Commissions for the
Salesmen
The Sales Commission program calculates every salesman's commission using the
same
rate. Now
we
will modify the program so that each salesman has his
own
commission rate. Here is a list
of
salesmen and their commission rates:
Name
ADAMS
JONES
LEE
SMITH
VINSON
Rate
15%
16%
18%
20%
14%
When any
of
the above names is entered, the program must look
in
the table to find
the corresponding rate before the commission can
be
calculated. Make the following
changes to the program:
Retype line 20 as follows
20
READ
NU
t
CR
S4
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