arrays -> pointers

Kevin Rushforth rushfort at esunix.UUCP
Wed Jan 20 03:56:33 AEST 1988


in article <3761 at sigi.Colorado.EDU>, swarbric at tramp.Colorado.EDU (SWARBRICK FRANCIS JOHN) says:
> 
> Here is a line of code that I got out of a book:
> 
> (*(mn+hsel-1)->func[vsel-1])(hsel,vsel);

Correct, assuming the following typedefs and variables (or some equivalent):

typedef void (*funcp)();
typedef struct
{
    funcp *func;
} mystruct;

mystruct *mn;
int vsel,hsel;

> With it using arrays in both places that would look normal I think it would
> look like this:
> 
> (*ms[hsel-1].func[vsel-1])(hsel,vsel);

Also, correct;

> ANyway, does anyone know how to get it to that it won't use *any* array
> brackets?  I tried stuff like:
> 
> (*(*(mn+hsel-1)->func+vsel-1))(hsel,vsel);

Not quite.  This should be written as:

    (**((mn+hsel-1)->func+vsel-1))(hsel,vsel);

In your example, you try to add (vsel-1) to the pointer (mn+hsel-1)->func
AFTER dereferencing it rather than before.  Hope this helps.
-- 
                Kevin C. Rushforth
                Evans & Sutherland Computer Corporation

UUCP Address:   {ihnp4,ucbvax,decvax,allegra}!decwrl!esunix!rushfort
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