Tandy TRS-80 Owner Manual & Programming Manual page 46

A
MORE
DIRECT
APPROACH
PROGRAMMING
EXERCISE
7.1
Change
lines
32
and
34 so that
your
Computer
will
use record 3
to
PUT
and
GET
"BILL SMITH."
itV-,
:
*W
;*&*&&*
,1
-
DEALING WITH
GARBAGE
You have not yet
PUT
anything
in record
1
.
Ask
the
Computer
to
GET
record
1
and
see
what
hap-
pens.
Type
this
and
RUN:
34 GET »1
>
1
Since the
Computer
didn't
PUT
anything
in
record
1,
record
1
contains
whatever "garbage"
is
already
there.
When
you ask
the
Computer
to
GET
and
INPUT
it,
it
will
either get
the "garbage" or give
you an
OS
(Out
of
String Space) error.
The
OS
error
sim-
ply
means
the
garbage
consumes more than 200
bytes
(characters).
Since
your
empty
records will
contain
garbage
until
you
fill
them
with something,
it's
a good
idea
to
put
some kind
of
data
in
all
of
them
in
advance.
Erase
memory
and
type this
program:
10
OPEN "D"
t
*1
i
"NAMES/DAT"
20
FOR
;;
=
1
TO 10
30
WRITE
*1
.
"NO
NAME"
40 PUT »l
,
X
50 NEXT
X
G0
CLOSE
«1
RUN
it.
This
program
sets
up
a disk
file
named
"NAMES/DAT"
which
has ten records.
Each
record contains
"NO NAME":
K
Mtie$fD#r"
"NO
NAME "
record
1
36
"NO
NAME"
record
2
"NO
NAME"
record
3
"NO
NAME"
record
4
"NO
NAME"
record
5
"NO
NAME"
record
6
"NO
NAME"
record 7
"NO
NAME"
record
8
"NO
NAME"
record 9
"NO
NAME"
record
10
juhjL
x
WfiM5S/D#T"
Now
erase
memory
and
type
this:
10
OPEN
"D"
i
#1
>
"NAMES/DAT"
20 INPUT
"RECORD
NO.
(1-10)
"i R
30
IF R
>
10
THEN
20
40
IF R
< 1
THEN 130
50 GET «1
.
R
G0
INPUT
«1
.
A$
70
PRINT
A$ "--
IS
THE NAME
IN
RECORD"
R