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Re: Class declaration: TMember Member(); vs TMember Member;

Cross-posted to 2 groups.

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On 6/21/2011 10:27 AM, Skybuck Flying wrote:
> Hello,
>
> I have a question about the parenthesis (see *) and further consequences
> of it in the following example class:
>
> class TSomeClass
> {
> TSomeOtherClass mSomeOtherClass1(); // *
> TSomeOtherClass mSomeOtherClass2;
>
> void SomeRoutine();

Explain to yourself the difference between

      sometype blah();
and
      someothertype blahblah();

and then explain to yourself the difference between

    TSomeOtherClass mBlah();

and

    void SomeBlah();

.  Perhaps after that you're going to see by yourself what the 
difference is between

     SomeType someName;

and

     SomeType someName();

(i.e. what the importance of the parentheses is).

> };
>
>
> void TSomeClass::SomeRoutine()
> {
> mSomeOtherClass1.SomeRoutine(); // does not compile
> // compiler error message:
> // error: nonstandard form for taking the address of a member function
> // error: expression must have class type
>
> mSomeOtherClass1->SomeRoutine(); // does not compile
> // error: nonstandard form for taking the address of a member function
> // error: expression must have pointer type
>
>
> mSomeOtherClass2.SomeRoutine(); // compiles just fine.
> }
>
> So what is the effect of the parenthesis at // *.

Read the FAQ section 10.

> To me it looked as if the default constructor for mSomeOtherClass1 was
> being called ?

Yes, that's common among beginners, we've pretty much all been there.

> But perhaps something else is happening which causes the
> mSomeOtherClass2.SomeRoutine call to fail to compile ?!
>
> Does mSomeOtherClass2 need to be "constructed" by calling it's
> constructor in the default constructor of TSomeClass or is that
> automatic (so when parenthesis in the member declaration are left out) ?.
>
> Bye,
> Skybuck.

V
-- 
I do not respond to top-posted replies, please don't ask

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Class declaration: TMember Member(); vs TMember Member; "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-21 16:27 +0200
  Re: Class declaration: TMember Member(); vs TMember Member; "Alf P. Steinbach /Usenet" <alf.p.steinbach+usenet@gmail.com> - 2011-06-21 16:36 +0200
  Re: Class declaration: TMember Member(); vs TMember Member; Victor Bazarov <v.bazarov@comcast.invalid> - 2011-06-21 10:33 -0400

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