Commodore RF512C - Random Access File

33
RANDOM ACCESS FILE
It is also calied RELATIVE FILE in this sys tem.
Programmer
can easy build- up t he file structure in to fields and
records without take care of the who le file in program.
T.he relative file
is es tablished by six side-sectors and each side-
sector has it
data pointer th at po int to individual data block.
Acco r ding to its formal, some DOS utl iti es can't work no rmally.
The fo ll ow ing demo pr ogr am shows you how to cr ea t e, wirte and
read the relative f il e.
10 DOPEN# 1. " REL,L 20"
20 RECORD# 1,30
30 DCLOSE 1
40
FOR 1=1 TO 10
50 DOPEN# 1. " REL ,L 20"
60 INPU T" NAME - "; NA$
70 IF LEN(NAME $) > 10 THEN 60
80 INPUT " TEL - :" ;TEL $
90 IF
LEN[TEL $» 10 THEN 80
100 D$=NAME$ +CHR$ (13) +TEL$
110 RECORD# 1,D$
120 PRINT# 1, D$
130 DC LO SE 1
140
NE XT I
150
FOR 1=1 TO 10
160 DOPENiI' 1, " REL ,20"
1
70 RECORD#' 1, (1), 1
180
INPUTii' 1, NAME $ ,TEL $
190
PRINT NAME$ ; ':"':', TEL $
200
DCLO SE 1
210 NE XT I
LINE 10 to 30: Create REL fil e
LINE 40 to 140: Write ten pairs of data onto it
LINE 150 to 210: Re ad da ta back fr om file
Because user
can easily r edef ine the record length. So, no
append function is need s.