can not the "static const int" be replaced by "static enum" anywhere?
is it necessary that define special initialization syntax for "static const int"? 3 12358
Ajax Chelsea wrote: can not the "static const int" be replaced by "static enum" anywhere?
enum is a type, not a variable, so it needs no 'static' storage category.
'int' has an implementation-defined size, and its type is compatible with
variable ints.
'enum' is only guaranteed to have enough bits to store any value used in
their definition.
For a while, compilers could not treat 'static const int' inside a class as
a compile-time constant, and so one couldn't size arrays with it and such.
Using 'enum' as a scalar instead of a typed flag was an easy work-around.
is it necessary that define special initialization syntax for "static
const int"?
?
Constant static data are the only things that can declare inside a class.
This (I suspect) grants them their compile-time constant status.
This is all well-formed, with defined behavior:
class yo { public:
static int z (42);
};
char whatever[yo::z];
But an enum would have worked the same, too.
--
Phlip
Phlip wrote in news:ey******** ***********@new ssvr32.news.pro digy.com: This is all well-formed, with defined behavior:
class yo { public: static int z (42); };
char whatever[yo::z];
But an enum would have worked the same, too.
Also if you also want to use the static integral constant in a
non-compile-time context you also need a definition outside the class,
/* Not in a header file (templates aside)
*/
int yo::z; /* Note no initializer */
int main()
{
int z = yo::z;
int const *zp = &yo::x;
}
enum's don't have this requirment, which is perhapse one way in which
enum's are "better" than static int const's.
Cranking the level of triviality up a notch. An instance of an enum
can also be a static integral constant,
#include <iostream>
struct A
{
enum B { C, D, E };
static B const b = A::E;
};
A::B const A::b;
int main()
{
std::cerr << A::b << "\n";
}
Rob.
-- http://www.victim-prime.dsl.pipex.com/
Rob Williscroft <rt*@freenet.RE MOVE.co.uk> wrote in message news:<Xn******* *************** ************@19 5.129.110.204>. .. Cranking the level of triviality up a notch. An instance of an enum can also be a static integral constant,
#include <iostream>
struct A { enum B { C, D, E }; static B const b = A::E; };
A::B const A::b;
int main() { std::cerr << A::b << "\n"; }
Rob.
so I consider that it is not necessary to specialize syntax of "static
const int(long...)", haha This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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