Path: utzoo!attcan!uunet!aplcen!samsung!usc!elroy.jpl.nasa.gov!ames!vsi1!octopus!sjsumcs!horstman
From: horstman@sjsumcs.sjsu.edu (Cay Horstmann)
Newsgroups: comp.lang.c++
Subject: Re: calling (con|de)structors explicitly
Keywords: c++1.2, constructor
Message-ID: <1990Feb11.164521.18287@sjsumcs.sjsu.edu>
Date: 11 Feb 90 16:45:21 GMT
References: <1088@tuvie>
Reply-To: horstman@sjsumcs.SJSU.EDU (Cay Horstmann)
Organization: San Jose State University
Lines: 22

In article <1088@tuvie> inst182@tuvie (Inst.f.Techn.Informatik) writes:
>
>I have a problem: I want to dynamically create an array of
>a class as a member of another class. Now I cannot use the 
>new operator, because the constructors of this class all
>have at least one argument. Thus, I'd like to allocate the 
>memory with malloc and call the constructor explicitly 
>for each element. Can I do anything to make 
>this legal:
>
>
In C++ 2.0, you can launch a constructor on a pre-allocated area, but
it is not a pretty sight. You say "new (p) X( arg )" to run X::X( arg ) on
the area of memory starting at p. 

See Lippmann for the details.

I suppose you are doing this because you don't own X--otherwise I
think it would make far more sense to add a X::X() and an explicit
function to do the initialization, say X::init( arg ). 

Cay