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Re: the last line of a large file [message #55326 is a reply to message #55246]

Fri, 10 August 2007 14:15

little davey
Messages: 5
Registered: June 2007

Junior Member

On Aug 9, 2:49 pm, queiny <quein...@yahoo.com> wrote:
> Hi,
>
> I am processing a large file with data in the same format till the
> last line. In the last line, it states how many records are included
> in this file.
>
> So the structure of my program is:
>
> while not eof(in_unit) do begin
> readf, in_unit, input_line
> if( input_line ne 'last line) then begin
> .....
> else
> ....
> endif
> endwhile
>
> Do I have to use 'if/then' to test whether every input_line is the
> last line of the file? Since there are many data records in the file,
> repeat calls to 'if/then' can be time consuming. But if I don't do the
> test, the program will be halted when it read in the last line.
>
> A Easy way I can think of is to delete the last line, but sometime we
> are not supposed to change the input files.

Would it be faster to use ON_IOERROR? One could process the "normal"
cases of reading the input lines. When there is an IO_ERROR, you trap
it and close the file. Naturally if there is a real IO_ERROR, you'd
have to test for a "real" input error, or the end of the file. But
that would mean IF statements executed only if there were IO_ERRORS.

-- Little Davey --

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[Message index]

		the last line of a large file By: queiny on Thu, 09 August 2007 12:49
		Re: the last line of a large file By: David Fanning on Tue, 14 August 2007 10:42
		Re: the last line of a large file By: queiny on Tue, 14 August 2007 10:22
		Re: the last line of a large file By: little davey on Fri, 10 August 2007 14:15
		Re: the last line of a large file By: James Kuyper on Fri, 10 August 2007 10:39
		Re: the last line of a large file By: Conor on Fri, 10 August 2007 08:51

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