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Comeau compiler complains (too few arguments for class template "B") at line
***

#include <memory>

template<typename T, size_t n>
struct A {};

template<typename T, size_t n>
struct B;

template<typename T>
struct B<T,2> {};

int main()
{
A<int,2> a;
B<float> b; // ***
}

What am I doing wrong?
--
Tom Tempelaere

TT (Tom Tempelaere) wrote in
news:ixxMb.8679$:

> Comeau compiler complains (too few arguments for class template "B")
> at line ***
>
> #include <memory>
>
> template<typename T, size_t n>
> struct A {};
>

Add a default here if that is what you want.

template<typename T, size_t n = 3 >


> template<typename T, size_t n>
> struct B;
>
> template<typename T>
> struct B<T,2> {};
>
> int main()
> {
> A<int,2> a;
> B<float> b; // ***
> }
>
> What am I doing wrong?

Your declaring a default, so you can't use a default.

Either add a sutible default or change line *** to

B< float, 3 > b;

HTH.

Rob.
--
http://www.victim-prime.dsl.pipex.com/

"Rob Williscroft" <> wrote in message
news:Xns946E8EBB3F680ukcoREMOVEfreenetrtw@195.129. 110.200...
> TT (Tom Tempelaere) wrote in
> news:ixxMb.8679$:
>
> > Comeau compiler complains (too few arguments for class template "B")
> > at line ***
> >
> > #include <memory>
> >
> > template<typename T, size_t n>
> > struct A {};
> >
>
> Add a default here if that is what you want.
>
> template<typename T, size_t n = 3 >

That is _not_ what I want to do.

> > template<typename T, size_t n>
> > struct B;
> >
> > template<typename T>
> > struct B<T,2> {};
> >
> > int main()
> > {
> > A<int,2> a;
> > B<float> b; // ***
> > }
> >
> > What am I doing wrong?
>
> Your declaring a default, so you can't use a default.

I am not declaring a default, I'm partially specializing a template class.
That has nothing to do with defaults!

> Either add a sutible default or change line *** to
>
> B< float, 3 > b;

That would make partial specialization totally unusable!

Do you actually know what partial specialization of a template class is?

> HTH.
>
> Rob.

Tom.

TT (Tom Tempelaere) wrote in
news:_jyMb.8737$:

> "Rob Williscroft" <> wrote in message
> news:Xns946E8EBB3F680ukcoREMOVEfreenetrtw@195.129. 110.200...
>> TT (Tom Tempelaere) wrote in
>> news:ixxMb.8679$:
>>

[snip]

>> Add a default here if that is what you want.
>>
>> template<typename T, size_t n = 3 >
>
> That is _not_ what I want to do.

Actually when you combine the default with the specialization, it
probably is, but you didn't say what you wanted to do.

>
>> > template<typename T, size_t n>
>> > struct B;
>> >
>> > template<typename T>
>> > struct B<T,2> {};
>> >
>> > int main()
>> > {
>> > A<int,2> a;
>> > B<float> b; // ***
>> > }
>> >
>> > What am I doing wrong?
>>
>> Your declaring a default, so you can't use a default.
>

Whoops missed a *not* in the above, It should have been:

Your not declaring a default, so you can't use a default.

> I am not declaring a default, I'm partially specializing a template
> class. That has nothing to do with defaults!

Yes you are, but then you try to use the class as if you had
given it a default for its second paramiter.

>
>> Either add a sutible default or change line *** to
>>
>> B< float, 3 > b;
>
> That would make partial specialization totally unusable!

You seem to be confused about what specialization does.

There can be only one class or class-template named B, if its
a class-template say B< typename, size_t > then it takes 2
arguments, specialization *isn't* overloading.

From your code above:

B< int, 1 > b1; // will instantiate the the unspecialized template.

B< int, 2 > b2; // will instantiate the specialization.

>
> Do you actually know what partial specialization of a template class
> is?

Yes *I* do.

>
>> HTH.
>>

Rob.
--
http://www.victim-prime.dsl.pipex.com/

"Rob Williscroft" <> wrote in message
news:Xns946E9DA786423ukcoREMOVEfreenetrtw@195.129. 110.205...
> TT (Tom Tempelaere) wrote in
> news:_jyMb.8737$:
>
> > "Rob Williscroft" <> wrote in message
> > news:Xns946E8EBB3F680ukcoREMOVEfreenetrtw@195.129. 110.200...
> >> TT (Tom Tempelaere) wrote in
> >> news:ixxMb.8679$:
> >>
>
> [snip]
>
> >> Add a default here if that is what you want.
> >>
> >> template<typename T, size_t n = 3 >
> >
> > That is _not_ what I want to do.
>
> Actually when you combine the default with the specialization, it
> probably is, but you didn't say what you wanted to do.
>
> >
> >> > template<typename T, size_t n>
> >> > struct B;
> >> >
> >> > template<typename T>
> >> > struct B<T,2> {};
> >> >
> >> > int main()
> >> > {
> >> > A<int,2> a;
> >> > B<float> b; // ***
> >> > }
> >> >
> >> > What am I doing wrong?
> >>
> >> Your declaring a default, so you can't use a default.
> >
>
> Whoops missed a *not* in the above, It should have been:
>
> Your not declaring a default, so you can't use a default.
>
> > I am not declaring a default, I'm partially specializing a template
> > class. That has nothing to do with defaults!
>
> Yes you are, but then you try to use the class as if you had
> given it a default for its second paramiter.
>
> >
> >> Either add a sutible default or change line *** to
> >>
> >> B< float, 3 > b;
> >
> > That would make partial specialization totally unusable!
>
> You seem to be confused about what specialization does.
>
> There can be only one class or class-template named B, if its
> a class-template say B< typename, size_t > then it takes 2
> arguments, specialization *isn't* overloading.
>
> From your code above:
>
> B< int, 1 > b1; // will instantiate the the unspecialized template.
>
> B< int, 2 > b2; // will instantiate the specialization.
>
> >
> > Do you actually know what partial specialization of a template class
> > is?
>
> Yes *I* do.

) I think I got it all screwed up. You are correct.

I'm sorry for questioning you.

Thanks,
Tom.

> >
> >> HTH.
> >>
>
> Rob.
> --
> http://www.victim-prime.dsl.pipex.com/