From: "G.B." <bauhaus@futureapps.invalid>
Subject: Re: Quick question regarding limited type return syntax
Date: Mon, 04 Aug 2014 12:42:42 +0200
Date: 2014-08-04T12:42:42+02:00 [thread overview]
Message-ID: <lrno32$9bl$1@dont-email.me> (raw)
In-Reply-To: <c491psFkt2bU1@mid.individual.net>
On 04.08.14 11:24, Niklas Holsti wrote:
> As I understand it, even in the languages which do
> have specific constructor/destructor facilities, there is no requirement
> or check that a constructor must initialize all the components of the
> object (but I'm not sure how Java works in this case).
Java lets you write Ada:
class T
{
public T() {
this.foo();
}
protected void foo() {}
}
class S extends T
{
public Integer I;
public S() {
// calls super
// I not initialized (and not allocated)
this.I = 1;
}
@Override
protected void foo() {
this.I += 1;
}
}
class Dispatching
{
public static void main(String[] args) {
S Y = new S();
}
}
This program will stop after throwing a NullPointerException.
If S.I is made an int, the default value is 0, and the above
program is considered bad style(*).
C++, I think, lets "this" stand for the type at the current "level"
during construction, so there is no dispatching to lower levels IIUC;
however, Stroustrup mentions some pointer tricks that let the
programmer circumvent the restriction.
(*) http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html
next prev parent reply other threads:[~2014-08-04 10:42 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-30 23:51 Quick question regarding limited type return syntax NiGHTS
2014-07-31 0:02 ` Adam Beneschan
2014-07-31 0:56 ` NiGHTS
2014-07-31 0:48 ` Shark8
2014-07-31 1:00 ` NiGHTS
2014-07-31 1:29 ` Adam Beneschan
2014-07-31 1:38 ` NiGHTS
2014-07-31 4:01 ` Shark8
2014-08-01 2:12 ` Randy Brukardt
2014-08-01 3:40 ` Shark8
2014-08-01 7:57 ` J-P. Rosen
2014-08-01 19:23 ` Randy Brukardt
2014-08-01 19:37 ` J-P. Rosen
2014-08-01 20:53 ` Shark8
2014-08-02 7:11 ` Niklas Holsti
2014-08-02 7:34 ` Dmitry A. Kazakov
2014-08-02 13:20 ` Robert A Duff
2014-08-02 13:44 ` Dmitry A. Kazakov
2014-08-02 14:34 ` Robert A Duff
2014-08-02 16:56 ` Dmitry A. Kazakov
2014-08-02 20:35 ` Niklas Holsti
2014-08-03 7:30 ` Dmitry A. Kazakov
2014-08-04 9:24 ` Niklas Holsti
2014-08-04 10:42 ` G.B. [this message]
2014-08-04 11:39 ` Peter Chapin
2014-08-04 17:49 ` Niklas Holsti
2014-08-04 11:36 ` Peter Chapin
2014-08-04 12:43 ` Dmitry A. Kazakov
2014-08-04 16:19 ` G.B.
2014-08-04 16:38 ` Dmitry A. Kazakov
2014-08-04 16:51 ` G.B.
2014-08-04 17:23 ` Dmitry A. Kazakov
2014-08-04 19:37 ` Niklas Holsti
2014-08-05 8:30 ` Dmitry A. Kazakov
2014-08-05 19:24 ` Randy Brukardt
2014-08-03 16:35 ` Robert A Duff
2014-08-02 8:02 ` Jacob Sparre Andersen
2014-08-02 19:20 ` Shark8
2014-08-03 16:07 ` Default values (Was: Quick question regarding limited type return syntax) Jacob Sparre Andersen
2014-08-04 21:29 ` Randy Brukardt
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