🚀 go-pugleaf

Dr. Richard Botting (dick@silicon.csci.csusb.edu) wrote:

>  According to the 2nd addition of Horstmann's "Mastering C++",
>  	cout << setiosflags(ios::fixed, ios::floatfield);
>  is OK, but I found that it would not compile because the libraries
>  on our Gnu C++ n.m.0 do not have a two argument form of the
>  iomanipulator setiosflags.

This must be a typo. It should read

   cout.setf(ios::fixed, ios::floatfield);

AFAIK, the library does not provide manipulators with two arguments.
You can, of course, easily write your own.

>  In the draft standard/working papers (HTML version) I searched
>  for all occurences of setisoflags and failed to
>  find anything but a one argument form:
>       smanip setiosflags  (ios_base::fmtflags mask);

>  Similarly for resetiosflags.

>  I presume that this is deliberate and that there is a
>  way of expressing the older pair of arguments in terms
>  of a single argument.

>  Am I right?
>  And if so... how does one do the euqivalent of
>  	cout.setf(ios:: F, ios::G);
>  by using
>  	cout<<setiosflags( X );

You can build manipulators with 2 parameters in different ways. I
prefer the manipulator to be a classname, so that M(x,y) is a
temporary object.

If you don't want to do that, you may write

   cout << resetiosflags(ios::floatfield) 
		<< setiosflags(ios::fixed);

although that is somewhat clumsy.

	Bernd

--
+----------------------------------+
|          Bernd Eggink            |
|    Rechenzentrum Uni Hamburg     |
| admin@rzaix13.rrz.uni-hamburg.de |
+----------------------------------+
---
[ comp.std.c++ is moderated.  Submission address: std-c++@ncar.ucar.edu.
  Contact address: std-c++-request@ncar.ucar.edu.  The moderation policy
  is summarized in http://dogbert.lbl.gov/~matt/std-c++/policy.html. ]