James Kuyper wrote:

> Wrong. The value of a ',' expression is the value of the second
> assignement expression.
>
> > 1.
> > int x =3D0;
> > x=3D4,x++,x++;
>
> x ends up with a value of 1.

My copy of the standard disagree,

Except where noted, the order of evaluation of operands of  individual
  operators  and subexpressions of individual expressions, and the order
  in which side effects take place, is unspecified.  Between the  previ-
  ous  and  next  sequence  point  a scalar object shall have its stored
  value modified at most once by the evaluation of an expression.   Fur-
  thermore,  the  prior  value  shall  be accessed only to determine the
  value to be stored.  The requirements of this paragraph shall  be  met
  for  each  allowable  ordering of the subexpressions of a full expres-
  sion; otherwise the behavior is undefined.  [Example:
          i =3D v[i++];      // the behavior is undefined
          i =3D 7, i++, i++; // 'i' becomes 9

          i =3D ++i + 1;     // the behavior is undefined
          i =3D i + 1;       // the value of 'i' is incremented
   --end example]


Pierre D=E9nomm=E9e


[ comp.std.c++ is moderated.  To submit articles, try just posting with ]
[ your news-reader.  If that fails, use mailto:std-c++@ncar.ucar.edu    ]
[              --- Please see the FAQ before posting. ---               ]
[ FAQ: http://reality.sgi.com/austern_mti/std-c++/faq.html              ]