Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!ucsd!orion.cf.uci.edu!paris.ics.uci.edu!bonnie.ics.uci.edu!schmidt
From: schmidt@bonnie.ics.uci.edu (Douglas C. Schmidt)
Newsgroups: comp.lang.c++
Subject: use of new allocator with reference variables
Keywords: c++, new, reference
Message-ID: <646@paris.ICS.UCI.EDU>
Date: 25 Aug 88 22:29:37 GMT
Sender: news@paris.ics.uci.edu
Reply-To: schmidt@bonnie.ics.uci.edu (Douglas C. Schmidt)
Distribution: na
Organization: University of California, Irvine - Dept. of ICS
Lines: 29
References:

Hi,

   I've been browsing through Stroustrup's C++ book and came
across the following puzzling construct on page 34:

Vec& sum = *new Vec(s);

I don't believe that this use of the new allocator (preceded by the
'*') is described anywhere else in the book.  Could someone please
explain the meaning of this, in the context of the function
depicted below?

Vec operator+(Vec a, Vec b) {
  int s = a.size();        
  if (s != b.size()) error("foo");
  Vec& sum = *new Vec(s);
  int *sp = sum.v;
  int *ap = a.v;
  int *bp = b.v;
  while (s--) *sp++ = *ap++ + *bp++;
  return sum;
}

thanks!

Doug Schmidt
--
schmidt@bonnie.ics.uci.edu (ARPA)
"If our behavior is strict, we do not need fun." -Zippy th' Pinhead
"If our behavior is struct, we do not need defun." -Anon