NetNews Usenet Archive 1992 #20/NN_1992_20.iso/spool/comp/lang/cplus/13394

Text File | 1992-09-08 | 1.4 KB | 48 lines

Newsgroups: comp.lang.c++
Path: sparky!uunet!taumet!steve
From: [e-mail] (Steve Clamage)
Subject: Re: Creating arrays of a class object using default constructor
Message-ID: <[e-mail]>
Organization: TauMetric Corporation
References: <[e-mail]>
Date: Tue, 8 Sep 1992 16:48:41 GMT
Lines: 37

[e-mail] (Mr. J.A. Coyne) writes:

>class compound  {
>   basic * array; // pointer to class basic
>public:
>   compound(); // class constructor function
>};

>compound::compound()  { array = new basic[10]; }

>class basic {
>    int * vector;
>public:
>      basic(int =5) ;
>};

>basic::basic(int size)  { vector = new int[size]; }

>The error message I recieve is  : default arguments for constructor for array
>of class basic(2005)

This is an area where the language has changed.  An array of objects
with a constructor require the "default constructor".  It used to be
that the "default constructor" was one which had no parameters, and a
constructor with all parameters defaulted was not a substitute.  The
newer language rule is that the "default constructor" is one which
does not require arguments, meaning that your code is now legal.

The cfront 2.1 compiler followed the old rule.  A workaround is to
make two constructors:

    basic()        { vector = new int[5]; }
    basic(int size) { vector = new int[size]; }
--

Steve Clamage, TauMetric Corp, [e-mail]
Vice Chair, ANSI C++ Committee, X3J16