* Is this explanation correct?
@ 2001-06-29 21:54 chris.danx
2001-06-30 0:30 ` Jeffrey Carter
0 siblings, 1 reply; 2+ messages in thread
From: chris.danx @ 2001-06-29 21:54 UTC (permalink / raw)
Hi,
The ps-programming@tutoraid.org mailing list seems a little dead at the minute
and it seems like the Ada folk are busy (I am no expert and don't want to
perpetuate misinformation).
A newbie posted asking
"There is something I don't understand about
end_of_file stuff. When I key in my data on the file in the floppy drive, if
I leave and save a space after the end data, I will get an End_Error . but
when I open the file back, and get rid of that space and save, and run the
program it works fine. can you tell me why?"
I want to check this before I relay it to the mailing list.
The program uses Ada.Integer_text_io which ignores spaces, so when the program
get's to the space it thinks there's an integer after it and it doesn't find
one, so it generates the end_error (exception) to let us know.
Is this correct?
Cheers,
Chris
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: Is this explanation correct?
2001-06-29 21:54 Is this explanation correct? chris.danx
@ 2001-06-30 0:30 ` Jeffrey Carter
0 siblings, 0 replies; 2+ messages in thread
From: Jeffrey Carter @ 2001-06-30 0:30 UTC (permalink / raw)
"chris.danx" wrote:
>
> A newbie posted asking
>
> "There is something I don't understand about
> end_of_file stuff. When I key in my data on the file in the floppy drive, if
> I leave and save a space after the end data, I will get an End_Error . but
> when I open the file back, and get rid of that space and save, and run the
> program it works fine. can you tell me why?"
>
> I want to check this before I relay it to the mailing list.
>
> The program uses Ada.Integer_text_io which ignores spaces, so when the program
> get's to the space it thinks there's an integer after it and it doesn't find
> one, so it generates the end_error (exception) to let us know.
>
> Is this correct?
It might be better to say that, with the space at the end of the file,
Ada.Integer_Text_IO.Get will stop before the space, so End_Of_File will
return False. Then the next call to Ada.Integer_Text_IO.Get will read
past the end of file looking for an Integer, causing End_Error to be
raised. With the space removed, Ada.Integer_Text_IO.Get will stop before
the line/page/file terminator, so End_Of_File will return True, and the
program will terminate normally.
--
Jeff Carter
"I wave my private parts at your aunties."
Monty Python & the Holy Grail
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2001-06-29 21:54 Is this explanation correct? chris.danx
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