Re: template declaration and definition

From:

Victor Bazarov <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Thu, 22 May 2008 08:09:30 -0400

Message-ID:

<g13npr$rk2$1@news.datemas.de>

ruebezaehler wrote:

I should separate the definition and declaration of template code. This
works fine for non-specialized templates. But I do not know how to do
this for specialized templates.

Example:

template<typename T>
class C_B
{
public:
    T var;
    public:
        C_B( void );
        virtual ~C_B( void );

Please, please, drop the habit of putting something between parentheses
where nothing is _meant_ to be there. It's C-ism, it's ugly.

};

template<typename T>
C_B<T>::C_B( void ) : var(0){ return;}

template<typename T>
C_B<T>::~C_B( void ) { return;}

// specialized for char*
template<>
class C_B<char*>
{
public:
    static const int MAXCHARS = 50;
    char* var;
public:
    C_B( void );
    virtual ~C_B( void );
};

// this won't compile

"Won't compile" - what does it mean? What error message do you get?

template<>
C_B<char*>::C_B( void )
    : var( new char[MAXCHARS+1] )
    {
    var[0]='\0';
    return;
    }

I think you're mixing two concepts. The 'template<>' syntax (verbatim)
starts a declaration/definition of a full specialisation of a template.
You already got that when you fully specialised class C_B template.
Now, when you deed to define the already specialised constructor from
that class, you should omit the 'template<>' construct and simply write

C_B<char*>::C_B() ...

Try it, let us know how it turns out.

V
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