Using an array as an index...

[SirLars]

Ok, this may seem like a stupid question, but... it just doesn't make sense to me...
even when looking at the MSDN site and through my C++ textbooks...

here's the sample code i am having problems grasping the logic....

VARIANT _stdcall retVariantArray(void) 
{
   COleSafeArray saRet;         
   DWORD numElements[] = {10, 10}; // 10x10

   // Create the 2 dimensional safe-array of type VT_R8 with size 10x10
   saRet.Create(VT_R8, 2, numElements);

   // Initialize safearray  with values...
   long index[2];
   for(index[0]=0; index[0]<10; index[0]++)
   {
      for(index[1]=0; index[1]<10; index[1]++)
       {
         double val = index[0] + index[1]*10;
         //populate the safearray elements with double values
         saRet.PutElement(index, &val);
      }
   }
   // Return the safe-array encapsulated in a VARIANT...
   return saRet.Detach();
}

now... if index is an array.. there can be index[0] and index[1]... right?

and PutElement is a function to put a value (in this case "val&quot into an array (in this case "saRet&quot... right?

and the first value is to be the index of the saRet array... right?

so, how does this function determine whether the value of index[0] or the value of index[1] is the proper index for this function?

OR.. is it because saRet is a 2 dimensional array.. that BOTH values of index (index[0] and index[1]) are used to find a place in saRet?

thanks in advance...

Lars.

 

[mingis]

> BOTH values of index (index[0] and index[1]) are used to find a place in saRet

seems like that.

 

[fheyn]

think of index[0] as i and index[1] as j.
For the 2-dimensional array you would have to pass i and j.
for a 5-dimensional array you would pass 5 indexes a.s.o.
But if you use index instead, you'll have to pass only ONE
variable, and PutElement accepts only ONE variable (which actually is a pointer). So every time you pass index, it addresses exactly ONE element of your target-array.
Hope this helps