template template classes

[Anonymous]

Could someone please explain template template classes, showing:

1). Why they are needed / i.e what problem do they solve ?
2). A simple example

I have read various articles etc, but it still dosen't seem to make
sense to me

[Barry]

Anonymous wrote:

Could someone please explain template template classes, showing:

1). Why they are needed / i.e what problem do they solve ?

template <class T, class Container>
class Stack1;

template <class T, template <classclass Container>
class Stack2

with Stack1, the template parameter Container needs container class
with Stack2, Container is a template template parameter, it need a class
with *one* template parameter.

see the usage:

class Vector1; // holds int

template <class T>
class Vector2;

Stack1<int, Vector1s1;
Stack1<int, Vector2<int s2;

Stack2<int, Vector1s3; // compile time error
Stack2<int, Vector2<int s4;

so template template parameter restrict the parameter you pass into the
template class.
Any other use, I don't know.

Anyway it's not mandatory, in STL, as far as I know, there's no template
template parameter usage.

2). A simple example

I have read various articles etc, but it still dosen't seem to make
sense to me

--
Thanks
Barry

[Barry]

Barry wrote:

Anonymous wrote:

>Could someone please explain template template classes, showing:

1). Why they are needed / i.e what problem do they solve ?

template <class T, class Container>
class Stack1;

template <class T, template <classclass Container>
class Stack2

with Stack1, the template parameter Container needs container class
with Stack2, Container is a template template parameter, it need a class
with *one* template parameter.

see the usage:

class Vector1; // holds int

template <class T>
class Vector2;

Stack1<int, Vector1s1;
Stack1<int, Vector2<int s2;

Stack2<int, Vector1s3; // compile time error
Stack2<int, Vector2<int s4;

My bad,
Stack2<int, Vector2s4;

>
so template template parameter restrict the parameter you pass into the
template class.
Any other use, I don't know.

Anyway it's not mandatory, in STL, as far as I know, there's no template
template parameter usage.

>2). A simple example

I have read various articles etc, but it still dosen't seem to make
sense to me

--
Thanks
Barry

[Frank Birbacher]

Barry schrieb:

Well, good example

Thanks! :D

but the /clumsy use/ of rebind is:

Allocator:: template rebind<Node>::other

Well, even worse. But seems you got the point. ;)

Frank