Re: MSVC++.NET 2002--> problems with overloaded constructor reference declarations

From:
benben <benhongh@yahoo.com.au>
Newsgroups:
comp.lang.c++
Date:
Mon, 12 Jun 2006 01:12:32 +1000
Message-ID:
<448c32e4$0$25130$afc38c87@news.optusnet.com.au>
raylopez99 wrote:

I'm having problems compiling complex reference declarations in
MSVC++.NET 2002 IDE.


What is a "complex reference declaration" btw?

Here is an example:

// --Foo.h--

#include "Bar.h"

class Bar; //forward decl. to a class Bar in another file, not used
here

class Foo
     Foo(Foo& Foo1);
 // Foo (void); // comment out since will fail to compile, see
below
     ~Foo(void);
private:
   Foo &refFoo1;
}


You need a left brace (ie "{") immediately after "class Foo"; and a
semicolon (ie ";") at the end of the class definition.

// -------- Foo.cpp --------

#include "foo.h"

Foo::Foo(Foo &Foo_1):refFoo1(Foo_1)

// Foo(void): refFoo1(Foo_1){} // comment out as fails to compile

{
}
////////////////////////

Now the above compiles, BUT, if I try overloading the normal
constructor along the lines of adding, in both Foo.h and Foo. cpp the
following, you get the infamous compiler errors C2758 and C2530 ('You
must initialize a reference when it is declared, unless...")


Add what to where? AFAICS "the following" is nothing much but an empty
block {} along with three lines of comments preceding it.

// this fails in Foo.h

// Foo(void);

// this fails in Foo.cpp

// Foo(void): refFoo1(Foo_1){}
{
}


I am guessing you are trying to do this:

    class Foo
    {
       Foo& refFoo1;

    public:
       Foo(void);
       Foo(Foo&);
    };

    Foo::Foo(void):refFoo1(Foo_1){} // line of error
    Foo::Foo(Foo& Foo_1):refFoo1(Foo_1){}

And the above failed to compile because the line of error refers to a
name "Foo_1" which didn't show up in the parameter list (ie, undeclared.)

However, this doesn't look like the error message you were getting. Post
a complete code in a single source file that reproduces your problem
please. Help us help you.

////////////

Any ideas as to why? BTW, if I try referencing a primitive data type,
like an int, "int &intREF", the above 'overloaded' normal constructor
_DOES_ compile (!). But complex assignments fail.


You just got me lost again.

I am curious but for my purposes even having a single constructor is
OK, but just curious as to why this fails. I've read that references
were in a state of flux as late as 1999, so perhaps this is a
bug/feature of the MSVC++ IDE (2002).


It is unlikely, though possible. I would put up a bet the compiler did
it right anyway. Post the *real* code from your IDE!

RL


Regards,
Ben

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