Commodore 1541 - Page 28

When using the INPUT*/ to read in data, the disk drive can't tell that it's not
supposed 10 be one long string. You need something in the file 10 act as a separator.
Characters to use as separators include the CR, a comma or a semicolon. The CR can
be added easily by just using one variable per line on the PRINT/* statement, and the
system puls one there automatically. The statement PRINTS 5, AS: PRINTS 5, BS:
PRINT# 5, CS puts a CR after every variable being written, providing the proper
separation for a statement like INPUT05, AS, B$, CS. Or else a line like
Z$= ",":PRINTS 5, AS Z$ BS Z$ CS will do ihe job as well, and in less space. The file
after that line looks like this:
char
M
1
E
2
L
3
L
A
0
S
6
\
;
L
H
L
1
ID
B
11
V
12
E
1)
TR
14
r.ll
15
Putting commas between variables resulls in lots of extra space on the disk being
used.
A statement like PRINTS 5, AS, BS makes a file that looks like:
char
II
1
fc
L
j
L
4
0
s
6 7 8 ')
10 11
A
12
1
13
1
14
rp
:j
You can see that much of the space in the file is wasted.
The moral of all this is: take care when using PRINTS so your data will be in order
for reading back in.
Numeric data written in the file takes the form of a string, as if the STRS function
had been performed on it before writing it out. The first character will be a blank space
if the number is positive, and a minus sign (-) if the number is negative. Then comes
ihe number, and the last character is the cursor right character. This format provides
enough information for the INPUTS statement lo read them in as separate numbers if
several are written with no other special separators. It is somewhat wasteful of space,
since there can be two unused characters if the numbers arc positive.
Here is a picture of the file after the statement PRINT** 5, 1; 3; 5; 7 is performed:
CK of
10 M
I 1
Appendix B contains a program demonstrating the use of a sequential disk file.
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