«

Hi,
I have a text file around 7GB includes 100 million lines...
I want to read the data line by line when I approach my module..

ie., when i read for the first time , my program shuld read only one
line
and when i read for the next time , my program shuld read only second
line discarding first line..

i did it with ignore function but it is taking lot of time to reach
end of file...

please give me a simple approch to do this..

thanks to all

xyz wrote:
> I have a text file around 7GB includes 100 million lines...
> I want to read the data line by line when I approach my module..
>
> ie., when i read for the first time , my program shuld read only one
> line and when i read for the next time , my program shuld read only
> second line discarding first line..

I'm not sure what you mean by "first time" and "next time" - do you mean
subsequent read calls with the open file, or do you mean reading a line,
closing the file, then opening it again and now reading the 2nd line?

In the first case, I don't see the problem, because you just read one
line after another.

In the second case, you'll need to store a filepointer somewhere
(variable or config file) - to the position AFTER your last read (i.e.
the first byte of the succeeding line). Then when you re-open the text
file, just jump to that file pointer and continue reading.

For info on ftell & fseek, check the c++ reference:
http://www.cplusplus.com/reference/c...dio/ftell.html


Best Regards,

Lars

On Jun 9, 2:09*pm, Lars Uffmann <a...@nurfuerspam.de> wrote:
> xyz wrote:
> > I have a text file around 7GB includes 100 million lines...
> > I want to read the data line by line when I approach my module..
>
> > ie., when i read for the first time , my program shuld read only one
> > line and when i read for the next time , my program shuld read only
> > second line discarding first line..
>
> I'm not sure what you mean by "first time" and "next time" - do you mean
> subsequent read calls with the open file, or do you mean reading a line,
> closing the file, then opening it again and now reading the 2nd line?
>
> In the first case, I don't see the problem, because you just read one
> line after another.
>
> In the second case, you'll need to store a filepointer somewhere
> (variable or config file) - to the position AFTER your last read (i.e.
> the first byte of the succeeding line). Then when you re-open the text
> file, just jump to that file pointer and continue reading.
>
> For info on ftell & fseek, check the c++ reference:http://www.cplusplus.com/reference/c...dio/ftell.html
>
> Best Regards,
>
> * *Lars

What i mean is....i want the second case...
i tried storing the file positon after reading the line...
but i couldnt succeed...
could you please get some more details

On Jun 9, 2:17*pm, xyz <lavanyaredd...@gmail.com> wrote:
> On Jun 9, 2:09*pm, Lars Uffmann <a...@nurfuerspam.de> wrote:
>
>
>
> > xyz wrote:
> > > I have a text file around 7GB includes 100 million lines...
> > > I want to read the data line by line when I approach my module..
>
> > > ie., when i read for the first time , my program shuld read only one
> > > line and when i read for the next time , my program shuld read only
> > > second line discarding first line..
>
> > I'm not sure what you mean by "first time" and "next time" - do you mean
> > subsequent read calls with the open file, or do you mean reading a line,
> > closing the file, then opening it again and now reading the 2nd line?
>
> > In the first case, I don't see the problem, because you just read one
> > line after another.
>
> > In the second case, you'll need to store a filepointer somewhere
> > (variable or config file) - to the position AFTER your last read (i.e.
> > the first byte of the succeeding line). Then when you re-open the text
> > file, just jump to that file pointer and continue reading.
>
> > For info on ftell & fseek, check the c++ reference:http://www.cplusplus.com/reference/c...dio/ftell.html
>
> > Best Regards,
>
> > * *Lars
>
> What i mean is....i want the second case...
> i tried storing the file positon after reading the line...
> but i couldnt succeed...
> could you please get some more details

i got it...thanks