Apple IIe - Page 224

224
Apple
lie Users
Handbook
150 INPUT
X$
160 PRINT
D$; "CLOSE
RANDOM
"
170 RETURN
180 INPUT "
ENTER
RECORD NUMBER
";
R
190 GOSUB 130
200
PRINT
X$
210
GOTO
180
Byte Parameter
The B
or
byte
parameter
can be used
with
the
READ,
WRITE,
and
POSITION
statements
to
move
the
file
pointer
to
a specified byte
with
in a
sequential
file
or
a specified
byte
within
a specified
field
in a
random
file
.
For
ex
ample
,
the
following
command:
WRITE
TEXT
A,
B20
would
set
the
file
pointer
to
the
twenty-first
byte
in
the
s
equen
tial
file
named
TEXT
A. The first byte
is
byte
0.
Any
characters
output
to
the
disk
file
by subsequent
PRINT
statements
will
replace existing characters in
TEXT
A
beginning
with
byte
21
.
If
R
is
specified,
the
B
parameter
sets
the
file
pointer
to
the
s
pecified
byte
in
the
record
indicated
by
R.
In
the
following
example:
READ
TEXT
A,
R20
,
B4
the
read
operation
will
begin at
the
fifth
byte in
the
twenty-first
rec
ord
.
When
using
the
byte
parameter
,
the
user must
know
exactly
what
data
ha
s
been
stored in
the
file
.
Remember
that
spaces,
c
omma
s,
return
codes, and
all
characters are stored in
byte
positions
with
in a
field
.