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From: Thorsten Ottosen (nesotto_at_[hidden])
Date: 2004-03-02 06:51:18

"Daniel Frey" <daniel.frey_at_[hidden]> wrote in message

>> Sorry, but I don't get this.
>> complex<float> z = float( pi );
>> should work just fine.
>Sure, but what about complex<float> z = complex<float>(pi)?


>think about a generic algorithm:
>template<typename T> T area(const T& r)
> return pi * r * r;

also works. At least for float, double, and long double. Do you mean that
your version will
work with physical quantities like meters? If so, could I achieve the same
effect by adding

template< typename T >
inline T operator*( T l, pi_t )
{ return something; }


>(or even T(pi)*r*r). You need constants that work well for all types
>with no special treatment of some types.

Given the info above, I can't fully understand it.

>>>shouldn't this scale to pi*pi*t? Or sqrt(pi)*t. The first non-constant
>>>should select the type, no matter how the constants are used before.
>> Yeah, I could let pi * pi return a two_pi object.
>No. OK, "yes" for this example, but "no" in general. You cannot predict
>all combinations the user could write. Simply providing all possible
>combinations is ridiculous overhead which doesn't scale well. My
>constant library works for any combination, whether predefined (that is,
>there is a real constant pi_square (ha, you got fooled by your own names
>- the naming dilemma! :) ) ) or not.

:-) Ok, but I don't quite see how your approach works for all combinations
coding support for them. But I'm willing to wait till you write some docs
about it to find out.



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