det_Z(A).r instead of z.r

Hello,

If the function det_Z(), is of this type :

complexZ det_Z(double **A);

Can I write :

do
{
r_mZ(A,999.);
printf(".");
}while(!det_Z(A).r);


instead of

complexZ z;

do
{
r_mZ(A,999.);
z = det_Z(A);
printf(".");
}while(!z.r);

Thank

http://groups.yahoo.com/group/mathc/

re: det_Z(A).r instead of z.r

"xhungab" <xhungab@yahoo.frwrote:
Sure, provided a complexZ has a member called r which is a scalar - but
if it didn't, your second snippet wouldn't work, either.

Richard

re: det_Z(A).r instead of z.r

xhungab wrote:You haven't completely specified the type, since you haven't told us
what a complexZ is. But it is clear that det_Z is a function that takes
a pointer to pointer to double, and returns a complexZ. Whatever that is.

You also haven't told us what this function is supposed to do.
How are we to know, without the declaration of r_mZ, A, and complexZ?

You haven't told us what type A is. It should be a pointer to pointer to
double, or perhaps pointer to void, if the above code is correct.

You haven't told us what type complexZ is. It should be a struct
containing at least one member, named r, of an arithmetic or pointer type.

You haven't told us what the type of r_mZ is. It should be a function
taking two arguments: (1) a pointer to pointer to double and (2) a
double. It should probably return void, but it may return something else
if you ignored its return value above.
The code above is equivalent to the previous code. The exception is that
the value of z is still available after the loop in case you still
wanted to use it.

I suppose the question should have been:

"Can I use the struct member access operator (.) directly
on the return value of a function?"

struct foo {int a;};

struct foo bar(void)
{
return (struct foo){0};
}

int main(void)
{
return bar().a;
}

The answer is, yes, you can.

--
Simon.

re: det_Z(A).r instead of z.r

You are right.
Thank for your answer.

Ps:

typedef struct
{
double r;
double i;
} complexZ,
*pcomplexZ;

It is a pointer on a complex matrix.
I have try to follow the indication given
into the group "comp.lang.c"
But I have customized the method.
double **A;

r for rand.
void r_mZ(double **A, int n);

det for determinant.
complexZ det_Z(double **A);