Re: enum v.s. static function in template class: which one is better ?
"Lizax" <lizax@126.com> writes:
I want to implement a template like this:
template<typename T, int id>
struct Foo
{
typedef T Type;
enum { value = id };
};
or
template<typename T, int id>
struct Foo
{
typedef T Type;
static int value() { return id; }
};
which one is better ?
That depends on your needs.
The first form probably has more uses, because
Foo<someT,someId>::value is a "compile time constant". This allows you
to use it in more situations than the return value of a function;
e.g. you can use it in other template instantiations.
On the other hand, you might have generic code relying on there being
a value() member function, and you want to use that code on the Foo
template as well. In that case, value() is part of the required
interface, so you have to provide it.
All other things being equal, I'd opt for the first form; it's also
the simpler one.
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