Re: Constant evaluation

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ZartPARZ wrote:
Could you told me adventage/disadventage of #define and const? (for
numerical constant) Which one I should use?

Macros are evil, see the C++ FAQ at parashift.com.

I have one more question, too, why did you quote this:

"Carl Daniel [VC++ MVP]" wrote:

ZartPARZ wrote:
Hi

If I have a code like

#define mass 2.4
#define g 9.8

double potential(double height)
{
return mass * g * height;
}

My question is the mass*g part will be calculate at compile time or
run-time? And if I use const double mass=2.4 instead, when is it
calculated?

In an optimized (Release) build, the compiler will perform the
calculation of mass*g at compile time regardless of whether you use a
#define or a const double.

-cd




?

Don't top-post, don't full-quote unnecessarily.

Uli

.

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