Radio Shack TRS-80 User Manual page 21

Type
in
the following:
10
REM *
DISTANCE,
RATE, TIME
PROBLEM
*E2Q33
(this
sure
is
a
slow computer).
20
R
=
500
30
T =
6
mm
to
D = r
* t
Gzoia
Check
the
program
carefully,
then
run ESE3
Hum
de
dum ho-hum
READY
All
it
says
is
READY
.
The Computer
doesn
't
work!
Yes
it
does.
It
worked
just fine.
The Computer
multiplied 500
times 6
just
like
we
told
it,
and came up
with the
answer of
3000 miles.
But
we
forgot to
tell it
to
give us
the answer.
Sorry about
that.
Can you
finish this
program without help?
It
only takes
one
more
line.
Give
it
a
good
try
before reading
on for
the answer.
That way,
the
answer
will
mean more
to
you. (Hint:
We've already used
PRINT
to print
messages
in
quotes.
What would happen
if
we
said
50
PRINT
M
D
"?..
.
No,
we want
the value of
D, not
"D"
itself.
Hmmm,
what happens
when we
get rid
of the quotes?)
RKED
ON.
THE
MOVE
1
:
J
.^
-:>:?-
<
vj
-
"
*"
"
DON'T
RE0
BEYOND;
}&AJZ'KL-Jiih,'
saw
Look
in
Part
B
of this
Manual
for an
answer
for this
1st Exercise.
Also
some notes and ideas.
Well,
the
answer
of
3000
is
correct,
but
its
"presentation"
was no
more
inspiring
than the
printout
from
a
hand
calculator.
This
inevitably leads us back to
where
we
first
started
this
foray into the
unknown
—
the
PRINT
statement.
Note
that
we
said in line
50
PRINT
D.
There were no quotes around
the letter
D
like
we
had
used
before.
The
reason
is
simple but
fairly
profound.
If
we want
the
Computer
to
print
the exact words
we
specify,
we
enclose
them
in quotes.
If
we want
it
to print the value
of a
variable, in this
case D,
we
leave
the quotes
off.
That simple message
is
worth
serious
thought before continuing on.
Yes,
yet
.
.
.we know:
the 'distance
from
Bos$qb
to
Saa Diego isefoser to
2§0y-r»H#$
'—
But
we
took
)
a <juick
detour
via
Bermuda
(besides,
3000
is
an
easiet^umbwtobe *orkh^with)?
Md
you
think seriously
aBout
it?!
you
go!
,
Then
oti
19