[snip: On May 6, 3:32 am, Ben Bacarisse <ben.use...@[EMAIL PROTECTED]
> wrote:
> "Michael.Z" <zhangqiuy...@[EMAIL PROTECTED]
> writes:
> > The Table.c was required to be implemented as generic type. If I am
> > right, Table is declared as void * in header file, the reason is that,
> > when used later on, it can be casted to any other type of pointers.
>
> > The implementation of Table in Table.c was defined as pointer to
> > struct Table, because I need to implement the members of Table.
> ]
> > My professor told us, void * in header indicates a generic type.
> > He has some sample codes where List wastypedef'd void pointer but the
> > definition was struct List Pointer:
>
> First, the more common way to "hide the implementation" is simply to
> declare your functions as using a 'struct Table *' (as has already
> been explained by Flash Gordon).
>
> Secondly, this does not stop you writing generic functions that have a
> 'void *' parameter. You can pass a 'struct Table *' where a 'void *'
> is expected when is im****tant to do so.
I just want to make sure I got you right.You are suggesting:
typedef struct Table{ ...} Table;
Table * makeTable( void* size, void * data);
> There is no obvious advantage to making the Table generic (in that
> sense) rather than simply hidden. In fact there is a positive
> *disadvantage* to doing that -- you loose all the type-checking. It
I don't quit understand this part.
"generic(in that sense)": refers to what I said about my professors
way.
vs
"simply hidden": the above example. Table * makeTable( void* size,
void * data);
> is usually much better to stick with hidden (incomplete) struct
> pointers right up to the point where you are *forced* to start using
> 'void *'.
an example of being *forced* would be:
void useTable(*void myTable){
Table * makeTable = (Table *)myTable;
}
if my example is not right, any chance you can give me correct one?
>
> Your professor may have a reason for doing this, but it does seem like
> a wise choice from the sample you posted.
>
> --
> Ben.
"
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