The right way to handle this difference in Ada

["vic" <ppp@ppp.it>]

Hello,

I'm starting to develope in Ada 95, but as I come from C++ language I'm
having some difficulties about strong typing.


Please consider this type:

type unsigned_int_12_type is range 0..(2*12)-1;

and these 2 variables of the above type:

a: unsigned_int_12_type;
b: unsigned_int_12_type;

If the code must perform a difference between a and b, say:

c := a-b

1) which should be the type of c? I think it should be something like:

type signed_int_12_type is range -unsigned_int_12'last ..
unsigned_int_12'last.

Is this right?

2) And I should rename a "-" operation which gets two signed_int_12_type  as
operands and returns signed_int_12_type as result?


Thanks,

vic