Hello everybody.

I've got such an aching me question concerning fast & well optimized
access to members of a structure (or class) and ways that VC compiler
handles it. Let's imagine the following structure and an array of its
type:

struct SSth1
{
   int nMbr1, nMbr2, nMbr3;
} aSth1[1000];

now, when I access members within a loop, I can do the following:

for (int i=0; i<1000; i++)
{
   for (int j=0; j<1000; j++)
   {
       doSth(j, &aSth1[i].nMbr1);
       doSth(j, &aSth1[i].nMbr2);
       doSth(j, &aSth1[i].nMbr3);
   }
}

The doSth is just a method modifying the given above variables. Now, I
can also do the following:

for (int i=0; i<1000; i++)
{
   int* nMbrLoc1=&aSth1[i].nMbr1;
   int* nMbrLoc2=&aSth1[i].nMbr2;
   int* nMbrLoc3=&aSth1[i].nMbr3;

   for (int j=0; j<1000; j++)
   {
       doSth(j, nMbrLoc1);
       doSth(j, nMbrLoc2);
       doSth(j, nMbrLoc3);
   }
}

I reckon that the second piece of code will be performed faster since
during execution of the code the pointers to the aSth1[i].nMbr1 will be
evaluated 1000 times rather than 1000*1000 times. Is that right? This is
what I assume. Alas, I do not know, how actually VC 2005 compiler
handles optimization issues like above. Can anyone elaborate a bit on
that? Do I have to follow that second way of coding, or, by any chance
compiler could handle pointer evaluation robustly on itself?

Cheers,
Peter.