Generics, use mathematical operatos on type parameter

[Jock]

Hi all,

I would like to use mathematical operators (*, +, etc) on a generic
parameter, see the code below:

public class TestGenerics<T> where ???
{
private T d;
public TestGenerics(int a)
{
d = a * 3;
}
}

Is this possible?
If yes, what constraint should I use on the T type argument?

Thanks
Jock

[Christoph Nahr]

On Sat, 04 Feb 2006 10:50:07 GMT, "Jock" <Jo**@nospam.com> wrote:

Is this possible?

No. You'll have to work around this problem with an interface or base
class that implements the required functionality.
--
http://www.kynosarges.de

[Jock]

>>Is this possible?

No. You'll have to work around this problem with an interface or base
class that implements the required functionality.

That what I suspected!
Unfortunately when you deal with native types (int, float, double, etc)
Generics are not so handy!
When will Microsoft provide us a useful Generics implementation similar to
C++ Template?!? :))

Jock

[Jock]

> When will Microsoft provide us a useful Generics implementation similar

to C++ Template?!? :))

For instance would be very handy having something like that:

public class TestGenerics<T> where T : numeric
{
private T d;
public TestGenerics(int a)
{
d = a * 3;
d = (d + 7) *5;
}
}

"where T : numeric" means that you can apply to T every math operator that
is supported by every numeric *primitive* types.
So the code in the constructor above will be valid!

What do you think?

Jock

[Christoph Nahr]

That would be quite useful. I suggest you submit your idea to the
MSDN Product Feedback Center so that the developers see it. In fact,
there's already a submission for operator restriction:

http://lab.msdn.microsoft.com/produc...c-36f1806d7ea8

You could vote for it so that MS is more likely to implement it for
the next release.
--
http://www.kynosarges.de

[Christoph Nahr]

Wait, here's another existing suggestion that's a bit closer to your
own proposal:

http://lab.msdn.microsoft.com/produc...1-8ce455606f72
--
http://www.kynosarges.de

[Jock]

You could vote for it so that MS is more likely to implement it for
the next release.

Christoph,

Thanks for your suggestion.
I an going to read and vote for the suggestions on the MSDN Product Feedback
Center you point
(I even didn't know that something like that exists!).

I hope we can achieve more power with Generics very soon.

Jock

[Andreas Mueller]

Christoph Nahr wrote:

Wait, here's another existing suggestion that's a bit closer to your
own proposal:

http://lab.msdn.microsoft.com/produc...1-8ce455606f72

Here's another:
http://tinyurl.com/8amzd

Here is an article describing the suggestion:
http://www.codeproject.com/csharp/genericnumerics.asp

HTH,
Andy
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