| eof | end-of-file function |
| Syntax | eof (streamNumber : int) : boolean
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| Description | The eof (end of file) function is used to determine if there
is any more input. It returns true when there are no more
characters to be read. The parameter and its parentheses are omitted
when referring to the standard input (usually this is the keyboard);
otherwise the parameter specifies the number of a stream. The stream
number has been determined (in most cases) by an open
statement.
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| Example | This program reads and outputs all the lines in the file called
"info".
var line : string
var fileNumber : int
open : fileNumber, "info", get
loop
exit when eof (fileNumber)
get : fileNumber, line : *
put line
end loop
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| Execute | |
| Details | See also the description of the get statement, which gives
more examples of the use of eof. See also the open
and read statements. When the input is from the keyboard, the user can signal end-of-file by typing control-Z on a PC (or control-D on UNIX). If a program tests for eof on the keyboard, and the user has not typed control-Z (or control-D) and the user has typed no characters beyond those that have been read, the program must wait until the next character is typed. Once this character is typed, the program knows whether it is at the end of the input, and returns the corresponding true or false value for eof.
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| Example | Another example is available that illustrates detecting EOF from
the keyboard.
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