Tandy TRS-80 Owner Manual & Programming Manual page 58

TRIMMING THE
FAT
OUT OF
OIRECT
ACCESS
record
1
IB
PAPER"*
record
2
*o?Fice/mT"
This obviously wastes a
massive
amount
of space.
Notice that
what
the
Computer
actually writes
in
each
record:
5,
"PEN"*
-IB,
"PAPER"*
is
the
same
as
what Program
1
wrote.
Count
the
bytes.
That's nine bytes
in
the
first
record
and
12
in
the second. You'll
need
to
know
this for
our next
program.
Note:
We
could have used
PRINT
or
PRINT USING
rather than
WRITE, The Computer would
have
then
PRINTed
your data inside each record using the
PRINT
or
PRINT USING
format.
TRIMMING THE
FAT
Program
6
is
the
same
as
Program
5,
except that
we
inserted a
number
12 at the
end
of
line 10,
This
tells
the
Computer
to
make
each
record 12 bytes
long:
PROGRAM
6
24 bytes
10
OPEN "B"i «lt
"OFFICE/DAT".
12
20
WRITE
»1
t
5
,
"PEN"
30 PUT »1
.
I
40 WRITE *1
,
-IB. "PAPER"
50 PUT
«1
t
2
B0 CLOSE
*1
and
really whittles this
file
down:
/
"OFFICE/ DAT"
5
,
"
p
E N "
*
record
1
1
G
*
"
P
A
P
E R "
*
record 2
"0FFIC£/DAT"
In a direct access
file,
all
records
must
be
the
same
length.
{We
explained
why
in
Chapter
7.)
If
you
don't
tell
the
Computer
how
long
to
make
them,
they
will all
be 256
bytes.
In this
program,
we made
each record 12
bytes,
the
size
of
the largest record.
Type
and
RUN
Program
6,
if
you'd
like,
(Be sure
to
erase
memory
and
KILL
your
old
"OFFICE/DAT"
file first.)
After
RUNning
Program
6
you
can use
this
program
to
input the
file:
48