TOPS-20 PASCAL Language Manual - Bitsavers

INPUT AND OUTPUT
7.9 THE PUT PROCEDURE
The PUT procedure appends a new component to the end of a file.
Fo rma t
PUT
(file va:riable);
where:
file variable specifies the file to which one or more
components will be written.
Before executing the PUT procedure, you must have executed the REWRITE
procedure. REWRITE clears the file and sets EOF to TRUE, preparing
the file for output. If EOF is FALSE, the PUT procedure fails; a
run-time error occurs; and program execution is terminated.
The PUT procedure writes the value of the file buffer variable at the
end of the specified file. After execution of the PUT procedure, the
value of the file buffer variable becomes undefined. EOF remains
TRUE.
Example
PROGRAM Bookfile (INPUT,OUTPUT,Books);
TYPE St T':i n~~~ :::: PACKED ARRAY [1 •• 40 J OF CHAR;
Book rec ::!: RECORD
Author : Strins;
Title : Strins
END;
VAR Newbook: Bookrec;
Books : FILE OF Bookrec;
N : INTEGER;
BEGIN
END.
F~EWR I TE (Books);
FOR N !: 1 TO 10 DO BEGIN
WITH Newbook DO BEGIN
WRITE ('Title:');
f~EAD (Title);
WRITE ('Author!');
READ (Author);
END;
Books- != Newbook;
PUT (Book~;)
END
This program writes the first 10 records into the file Books. The
records are input from the terminal to the record variable Newbook.
They consist of two 40-character strings denoting a book's author and
title. The FOR loop accepts 10 values for Newbook, assigning each new
record to the file buffer variable BooksA. The PUT statement writes
the value of Books A into the file for each of the 10 records input.
7-15