Radio Shack TRS-80 model III Owner's Manual page 143

Sample
Program
1310 At
=
"WILLIAM WILSON"
1320 GET
1
<+l
1330
IF N$
=
A$ THEN PRINT "FOUND
IN RECORD" LOC(l): CLOSE-
END
1340 GOTO 1320
This
is
a portion
of
a program. Elsewhere
the
file
has been opened and
fielded
n$
is
a
field variable.
If
n$ matches a$
the record number
in
which
it
was
found
is
printed.
LOF
Get
End-Of-File
Record Number
lor(nmexp)
nmexpsp
'^mmim
:
mwmexfi=
1,2,.. ..is.
This function
tells
you
the
number
of
the
last, i.e.,
highest numbered,
record
in a
file. It is
useful for
both
sequential
and random
access.
For example, during
random
access
to a pre-existing
file,
you
often need
a
way
to
know when
you've
read
the
last valid record, lof
provides
a way.
lof
is
valid as soon
as a previously created
file
is
opened.
If a
file is
extended
lof
is
not
valid
until a
get
is
executed.
Examples:
10
OPEN
"R"
,1
."UNKNOWN/TXT"
20 FIELD
1
,255 AS A$
30
F0RI%=1
TO L0F(1)
40 GET
1
,11
50 PRINT
A$
60
NEXT
In
line
30,
lof(d
specifies the
highest record number
to
be
accessed.
Note:
If
you
attempt
to
get
record numbers beyond
the end-of-file
record basic
simply
fills
the
buffer with hexadecimal
zeros, and no
error
is
generated.
'
142