Commodore 1541 - Page 45

Let's assume we have a mailing list. The list consists of 8 pieces of data, according
to this chart:
Field Name
first name
last name
address line 1
address line 2
city
state
zip code
phone number
Le
12
15
20
20
12
2
9
10
TOTAL 100
This is how the record length is determined. We would probably want to allow an
extra character in length for each field, to allow for separations; otherwise the INPUTS
command would pick up a much longer piece of the file than needed, just like in se
quential files. Therefore, we'll set up a file with a length of 108 characters per record.
In the first record, we'll put the number 1, representing the largest records used so far.
Here is the program as described so far:
5 X = 0
10 OPENl.8,15
20 OPEN2,8,3,"0:MA1L1NG LIST,L, " + CHRS(108)
30 GOSUB900
40 PR1NT#1,"P"CHRS(3 + 96)CHR$(1)CHRS(O)CHRJ(1)
50 GOSUB900
60 1FE = 50THENPRINT#2,1:GOT040
70 1NPUTS2.X
75 PRINT X
300 STOP:CLOSE1;CLOSE2;END_
900 INPUT#1,E,BS,C,D'
910 IF (E = 50) OR (E<20) THEN RETURN
920 PRINT E;BS;C;D:STOP:RETURN
Error #50 which is checked in line 60 of the program is Ihe RECORD NOT PRE
SENT error, which means that the record hadn't been created yet. Writing into the
record will solve the problem. This error condition must be watched carefully within
your programs.
39