Commodore PET User Manual page 270

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A good way to CLOSE a file that is being read is to test for an End of File
(EOF) with the STATUS WORD (ST). When the data file was written. an EOF
mark was written at the end of the file. When an EOF mark has been found. the file
status equals 64 and the file may be closed. You may test for an EOF mark and
close the file in one statement:
IF ST=64 TH EN CLOSE 1
When ST equals 64. the file will automatically CLOSE.
Reading Numbers with INPUT#
Previously we wrote the pragram NUM.PRINT# to write the numbers 1
through 10 on the data tape NUMBERS. where each number was written as a
single record. Now we will write a program called NUM.INPUT# to read the ten
numbers from the NUMBERS data file. and print them on the screen.
To read numbers and strings from a data tape the INPUT# command is
used. INPUT# reads one data item at a time. the data items being separated by a
semicolon. comma. or carriage return.
INPUT#f.var
where:
is the logical file number (1-255. matching the file number in the OPEN and
CLOSE command).
var is the variable name(s) of the data to be read.
The first few lines of NUM.INPUT# instruct the user to load the data tape.
These lines are identical to the first three lines of NUM.PRINT#. At line 30 is the
wait loop allowing the user time to mou nt the data tape. After mounting the tape.
key RETURN; the program continues at the next line.
10
PR!tH"~.
READ NUMER 1C DATA TAPE •• ": PR 1NT
20 PRINT" •• MOUNT TAPE; PRESS <RETURN.> WHEN READY •• ":PRINT
30 GET A$: IF A$="" THEN 30
Before we can read any data. we must open the data file. Line 40 opens file #1.
physical device #1. and secondary address 0 (OPEN for read) with filename NUM-
BERS.
4(1
PF~INT" •• OpnlING DATA FILE •• ": OPEN 1 .. 1,
(1 .•
"NUMBERS" : F'RItH
Next. a FOR ... NEXT loop is set up to read the first ten data items fram the
tape and print to the screen:
50 FOR 1=1 TO 10
60 INPUT#l, N
read N from tape
7(1
PR 1NT N
print N on screen
80 NEXT 1
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