From: "bowman" <bowman AT montana DOT com>
Newsgroups: comp.os.msdos.djgpp
References: <HhOCsDAf$YN3EwuI AT dunvegan1 DOT demon DOT co DOT uk> <0jzu8AArMaN3EwpJ AT dunvegan1 DOT demon DOT co DOT uk> <UTmZ2.2585$mW3 DOT 16026 AT newsfeed DOT slurp DOT net> <37374ACB DOT BA48C9DF AT unb DOT ca>
Subject: Re: Converting numbers to strings
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Message-ID: <7mMZ2.420$l%4.2872@newsfeed.slurp.net>
Date: Mon, 10 May 1999 20:11:17 -0600
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To: djgpp AT delorie DOT com
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Reply-To: djgpp AT delorie DOT com


Endlisnis <s257m AT unb DOT ca> wrote in message news:37374ACB DOT BA48C9DF AT unb DOT ca...
> >      ostrstream ostr;
> >      for (int i=0; i<20; i++) {
> >          ostr << "pic" << setfill('0') << setw(3) << i << ".bmp" <<
ends;
> >          cout << "filename = " << ostr.str() << endl;
> >          ostr.seekp(0);

>     What is the "seekp" there for?

ostr grows with each iteration of the loop. If you remove the 'ends' you can
watch it. With the 'ends', ostr.str() will always return 'pic000.bmp'.
Using seekp(0) resets the pointer, causing each iteration to overwrite the
previous one, and display correctly.

The example is a little contrived; in many cases, you would use the
ostrstream once, and it would go out of scope, and wouldn't hang around
collecting garbage.