Texas Instruments TI-99/4A - Page 149

INPUT
The EOF function cannot be used with RELATIVE files or with
somp: .:'l('r'.pssory c1f'vir'p<:, Tn thf':~f' r.::I~f':S, yOIl will np.f'o to ~reate your
own method for determining that the end·of·file has been reached.
Onf' ('ommon pno-of-filp: tp.chniQue is to create a last record on the
file that serves as an end-of-file indicator. It is called a "dummy"
record because the data it contains is used only to mark the end of
the file For examplp:, it mlllr! hf': filled with "9's." Whenever the
computer inputs a record, you can check the data. If it is equal to
"9's:' then the computer has reached end-of-file and can skip to the
closing routine
The first example on the right creates a dummy record. In the next
example, the computer checks for the dummy record as its end-of-
file technique.
Examples:
>N EW
>100 OPEN #2: "cs1 ",SEQUENTIAL
,FIXED,OUTPUT,INTERNAL
>110 READ A,B,C
>120 IF A=99 THEN 180
>130 E=A+B+C
>140 PRINT A;B;C;E
>150 PRINT #2:A,B,C,E
>160 GO TO 110
>170
DATA 5,10,15,10,20,30,10
0,200,300,99,99,99
>180 PRINT #2:99,99,99,99
>190 CLOSE #2
>200 END
>RUN
* REWIND CASSETTE TAPE Cs1
TIICN f'RESS ENTER
* PRESS CASSETTE RECORD CS1
THEN PRESS ENTER
5 10 15 30
10 20 30 60
100 200 300 600
* PRESS CASSETTE STOP CS1
THEN PRESS ENTER
** DONE **
>NEW
>100 OPEN #1:"CS1",INTERNAL,I
NPUT,FlXED
>110
INPUT #1:A,B,C,E
>120 IF A=99 THEN 160
>130
F=A*E
>140 PRINT A;B;C;E;f
>150 GOTO 110
>160
CLOSE #1
>170 END
>RUN
* PRESS CASSETTE PLAY CS1
THEN PRESS ENIER
5 10 15 30 150
10
20 30 60 600
100 200 300 600 6000
Cassette Recorder Information
• RELATIVE file'organization cannot be used with
Ci:t~~etle dev ices.
• The EOF (End·of·File) function cannot be used with files
on cassette recorders.
• You may specify a record length up to 192 positions (see
"OPEN')
• Only cassette unit 1 (CS 1) can be used for inputting
data,
User's Reference Guide
* REWIND CASSETTE TAPe
THEN PRESS ENTER
* PRESS CASSETTE STOP
THEN PRESS ENTER
** DONE **
C~l
CS1
11·129