In article mf8@rational.rational.com, "J\ir\tme Desquilbet" <jDesquilbet@Rational.COM> writes:
>
>Reading the STL part of the CD, I understand that the sample "Hello world"
>program becomes:
>
>#include <iostream>
>int main()
>{
>  using namespace std;
>  cout << "Hello, world!" << endl;
>}

That is one way to write it. There are other ways as well. You could put
the "using namespace" at file scope, or just have using-declarations
for the items you need from <iostream>.

>If yes, what about "old" programs written using <iostream.h>? What does the
>above program become if I want to write it without using namespace std?

The ".h" versions of the standard C++ headers are not mentioned in the standard.
Implementors may supply as many other headers as they like, with any sort of
contents. I would expect a vendor to supply a header corresponding to the
use of <iostream.h> which looked something like this:
 #include <iostream>
 using std::ios;
 using std::istream;
 using std::ostream;
 using std::cout;
 using std::cin;
 ... etc

Such a header would allow typical existing programs to continue to compile.
---
Steve Clamage, stephen.clamage@eng.sun.com



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Reading the STL part of the CD, I understand that the sample "Hello world"
program becomes:

#include <iostream>
int main()
{
  using namespace std;
  cout << "Hello, world!" << endl;
}

Am I right?

If yes, what about "old" programs written using <iostream.h>? What does the
above program become if I want to write it without using namespace std?

Thanks in advance,

  J   r   me.


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"J\ir\tme Desquilbet" <jDesquilbet@Rational.COM> wrote:
>
>Reading the STL part of the CD, I understand that the sample "Hello world"
>program becomes:

By a using directive:

>#include <iostream>
>int main()
>{
>  using namespace std;
>  cout << "Hello, world!" << endl;
>}
>
>Am I right?

     Thats one way. Here's another with explicit qualification:

#include <iostream>
int main()
{
  std::cout << "Hello, world!" << std::endl;
}

     Here's another with the compatibility header:

#include <iostream.h>
int main()
{
  cout << "Hello, world!" << endl;
}

     Here's another with using declarations:

#include <iostream>
using std::cout;
using std::endl;

int main()
{
  cout << "Hello, world!" << std::endl;
}


>If yes, what about "old" programs written using <iostream.h>?

    Should continue to work. iostream.h looks basically like:

// file: iostream.h
#include <iostream>
using std::cout;
using std::endl;
using std:istream;
...... (all names are 'used')


--
John Max Skaller               voice: 61-2-566-2189
81 Glebe Point Rd              fax:   61-2-660-0850
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AUSTRALIA                      email: skaller@maxtal.com.au



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>>>>> "SC" == Steve Clamage <clamage@Eng.Sun.COM> writes:

 SC> The ".h" versions of the standard C++ headers are not mentioned in the
 SC> standard.
 (...)
 SC> Such a header would allow typical existing programs to continue to
 SC> compile.

But, of course, every one of those existing programs is non-standard.

Michael.
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John Max Skaller <maxtal@suphys.physics.su.oz.au> wrote:
>
>  #include <iostream>
>  using std::cout;
>  using std::endl;
>
>  int main()
>  {
>    cout << "Hello, world!" << std::endl;
>  }
>

Thanks for your answer.
I suppose you mean:

  #include <iostream>
  using std::cout;
  using std::endl;

  int main()
  {
    cout << "Hello, world!" << endl;
  }

And what about <<?
Is not something like:

  using std::operator<<;

necessary?

  Jerome.
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John Max Skaller <maxtal@suphys.physics.su.oz.au> wrote:
>
>  #include <iostream>
>  using std::cout;
>  using std::endl;
>
>  int main()
>  {
>    cout << "Hello, world!" << std::endl;
>  }
>

Thanks for your answer.
I suppose you mean:

  #include <iostream>
  using std::cout;
  using std::endl;

  int main()
  {
    cout << "Hello, world!" << endl;
  }

And what about <<?
Is not something like:

  using std::operator<<;

necessary?

  Jerome.



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Distribution:
  >> But, of course, every one of those existing programs is
  >> non-standard.

   Since we as yet have no standard, every one of _ALL_ existing
programs are non-standard.


[Moderator's note: I think that "non-standard" in the original post is
simply shorthand for "non-standard under the assumption that there
will be no major changes to the rules in the current draft."  Still,
it's worth remembering that the draft isn't a standard.  mha]

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