Re: Pointer of Reference ?

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From: Michael Schlenger (Michi-Schlenger_at_web.de)
Date: 06/14/04 

Date: Mon, 14 Jun 2004 18:11:32 GMT

On Fri, 11 Jun 2004 17:34:04 -0400, Joseph M. Newcomer
<newcomer@flounder.com> wrote:

>It also saves you from that ugly misfeature of C where you must use . for objects and ->
>for pointers (but if you get it wrong, the compiler complains. Of course it never occurred
>to the language designers that if the compiler can tell the difference, the programmer
>shouldn't need to!).

I see it exactly the other way around. A pointer is something
completely different from a reference, and you should make it damn
clear in your code what you mean. It is good that the compiler tells
you if you do something other that you mean - that is, "the compiler
is your friend", as I always say.

More general, it usually is NO GOOD IDEA to have the compiler make
assumptions about what you might have intended. Things like

        void f( int );
        f( "5" );

simply should not compile although there is an obvious semantic
interpretation of the two statements.

[snip]

> ASSERT(pDC != NULL);
> ASSERT(pBitmap != NULL);

is there any reason why you do not simply write

        ASSERT( pDC );

Do you also write

        if ( someBool == true )

?

BTW, in C++ the null pointer is noted as 0, NULL is not part of the
language, it is some library thing.

[snip]

>Some will argue that putting the & at the call site makes it obvious that the object can
>be modified, but I think this argument is specious.

This argument is completely wrong. To specify that a server does not
modify an object, the language provides the const specifier.

For some type T, the statements

        void f( const T& );
        void f( const T* );

both signal to the caller that the function cannot modify the object.
That has nothing to do with the pointer/reference thing. The good
thing of course is that the compiler can enforce this - again: the
compiler is your friend.

------------------------------------------------
Michael Schlenger
------------------------------------------------

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