TOPS-20 PASCAL Language Manual - Bitsavers

INPUT AND OUTPUT
The first reference to the file INPUT is the EOLN test in the WHILE
statement. When the test is perfor~ed, the system attempts to read a
line of input from the text file. Therefore, it is very important to
prompt for the integer or empty line before testing for ROLN.
Suppose you respond to the first prompt by supplying an integer as
input. Access to the input device is delayed until the EOLN function
makes the first reference to the file INPUT. The EOLN function causes
a line of text to be read into the internal line buffer. The
subsequent READLN procedure reads the input value from the line of
text 8nd assigns it to the variable I. The WRITELN procedure writes
the input value to the text file OUTPUT. The final statement in the
WHILE loop is the request for another input value. The loop
terminates when the EOLN detects the end-of-line marker.
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