Owner`s manual
21
•
• To find
the
data end
What would happen if the data being read-out in order from the file surpass the
number of data registered? In this case, an error does not occur. And a zero
or
blank
is
set
in
the read-out variable, but there
is
a special function
EOF
(#n)
(page 56)
which can detect the data end. When there
is
a data read-out by an INPUT command,
EOF
(#n)
becomes a true condition when there
is
no data.
As a result, if the
IF
EOF
(#n)
THEN
command
is
placed after the INPUT # command, then if
EOF
(#n)
becomes "true",
i.e. if the end
of
the data
is
found, the command after
THEN
will
be executed.
Here use the practice problems to become sufficiently accustomed to the use of the
BSD file.
Practice problems
Problem 1
Using the program example on the previous page, change the program assuming that
the number
of
people registered
is
unknown, read-out the file
10
persons at a time
until the end of the file
is
reached and display them.
Example solution
The following program might, for example, be considered.
300
ROPEN
#5,
" F D 1
ADDRESS
LI
ST"
3 1 0
FOR
I
=1
TO
1 0
320
INPUT
#5,
NA$,
AD$
330
I F E
OF
(
#5)
THEN
400
350
NEXT
360
PRI
NT
" PUSH
SPACE
KEY"
370
GET
X$: I F
X$
THEN
310
380
GOTO
370
400
CLOSE
#5
410
PRI
NT
" F I
LE
END" :
END