TITLE: Setting output width with iostreams



PROBLEM: LEVITTE@e.kth.se (Richard Levitte)

I personally like the C++ iostreams very much, and I find the
operator<<(ostream&, <whatever>) quite usable, except for one
thing. There is no way, as far as I know, to specify a field
size for some particular argument to output.

What I would like is something similar to printf("%6.4f", f)!
Is this possible? Is there some predefined manipulator I can
use, or do I have to do this myself?



RESPONSE: steve@taumet.com (Steve Clamage), 1 Mar 93

Use the "width" and "precision" functions in the stream.  The
give effectively the same result as with printf formats.

	cout.width(6);
	cout.precision(4);
	cout << f;

More conveniently, two manipulators are provided in <iomanip.h>:

	cout << setw(6) << setprecision(4) << f;