ifstream: ignoring last line of file

[Ridimz]

When use ifstream, how do I ignore the last line of a file if it doesn't
contain any information?

Thanks in advance,
Ridimz

[WW]

Ridimz wrote:

When use ifstream, how do I ignore the last line of a file if it
doesn't contain any information?

Post code. The "normal" extraction operator *will* ignore it.

--
WW aka Attila

[Ridimz]

"WW" <wo***@freemail .hu> wrote in message
news:bl******** **@phys-news1.kolumbus. fi...

Ridimz wrote:

When use ifstream, how do I ignore the last line of a file if it
doesn't contain any information?

Post code. The "normal" extraction operator *will* ignore it.

--
WW aka Attila

searchID = 0;
do
{
searchID++;
entry.recNum = searchID;
acctFile >> entry.acctID;
entry.recNum = searchID;
acctFile >> acctRec.firstNa me >> acctRec.lastNam e >> acctRec.balance ;
acctRec.acctID = entry.key();
index.insert(en try);
} while (!acctFile.eof( ));

[Ridimz]

Sorry I accidentally submitted before I was done.

searchID = 0;
do
{
searchID++;
entry.recNum = searchID;
acctFile >> entry.acctID;
entry.recNum = searchID;
acctFile >> acctRec.firstNa me >> acctRec.lastNam e >> acctRec.balance ; acctRec.acctID = entry.key();
index.insert(en try);
} while (!acctFile.eof( ));

If there is a blank line following last line of information, it processes
last line of info a second time.

How do I prevent that?

Thanks

[WW]

Ridimz wrote:

When use ifstream, how do I ignore the last line of a file if it
doesn't contain any information?

Post code. The "normal" extraction operator *will* ignore it.

searchID = 0;
do
{
searchID++;
entry.recNum = searchID;
acctFile >> entry.acctID;
entry.recNum = searchID;
acctFile >> acctRec.firstNa me >> acctRec.lastNam e >>
acctRec.balance ; acctRec.acctID = entry.key();
index.insert(en try);
} while (!acctFile.eof( ));

As far as I see this will ignore it. Since the extraction operator starts
by skipping whitespaces and an empty line is a whitespace.

--
WW aka Attila

[WW]

Ridimz wrote:

Sorry I accidentally submitted before I was done.

searchID = 0;
do
{
searchID++;
entry.recNum = searchID;
acctFile >> entry.acctID;
entry.recNum = searchID;
acctFile >> acctRec.firstNa me >> acctRec.lastNam e >>
acctRec.balance ; acctRec.acctID = entry.key();
index.insert(en try);
} while (!acctFile.eof( ));

If there is a blank line following last line of information, it
processes last line of info a second time.

How do I prevent that?

One example:

searchID = 0;
do {
if (!(acctFile >> entry.acctID)) break;
if (!(acctFile >> acctRec.firstNa me >>
acctRec.lastNam e >>
acctRec.balance )) break;
entry.recNum = ++searchID;
acctRec.acctID = entry.key();
index.insert(en try);
} while (!acctFile.eof( ));

This will also skip the last record if it is incomplete!

--
WW aka Attila

[Ridimz]

"WW" <wo***@freemail .hu> wrote in message
news:bl******** **@phys-news1.kolumbus. fi...

This will also skip the last record if it is incomplete!

--
WW aka Attila

That did the trick! Thank you very much.
One last question: Say I just wanted to read the first entry on each line
(acctID), how would I go about doing so?

I currently read in all values on the line: which is unnecessary, because I
only need the acctID.

Thanks again!
Ridimz

[WW]

Ridimz wrote:

"WW" <wo***@freemail .hu> wrote in message
news:bl******** **@phys-news1.kolumbus. fi...

This will also skip the last record if it is incomplete!

--
WW aka Attila

That did the trick! Thank you very much.
One last question: Say I just wanted to read the first entry on each
line (acctID), how would I go about doing so?

I currently read in all values on the line: which is unnecessary,
because I only need the acctID.

You cannot, it is not a database table. But you can read the rest into the
same variable and simply not use it for anything. Or you can use getline
with a string, put that string into an istringstream and only read the first
thing out of it.

--
WW aka Attila

[Ridimz]

"WW" <wo***@freemail .hu> wrote...

You cannot, it is not a database table. But you can read the rest into the same variable and simply not use it for anything. Or you can use getline
with a string, put that string into an istringstream and only read the first thing out of it.

--
WW aka Attila

You've been very helpful!

Thanks,
Ridimz

[Kevin Goodsell]

Ridimz wrote:

searchID = 0;
do
{
searchID++;
entry.recNum = searchID;
acctFile >> entry.acctID;
entry.recNum = searchID;
acctFile >> acctRec.firstNa me >> acctRec.lastNam e >> acctRec.balance ;
acctRec.acctID = entry.key();
index.insert(en try);
} while (!acctFile.eof( ));

This is a poor way for checking if you've reached the end of the file.

http://www.parashift.com/c++-faq-lit....html#faq-15.5

-Kevin
--
My email address is valid, but changes periodically.
To contact me please use the address from a recent posting.