troubleshooting Question

problems with pointer arithmetic

Avatar of mordekai
mordekai asked on
C
14 Comments1 Solution391 ViewsLast Modified:
Here's the code:  (ignore the fact that it's in a class)

///////////////////////////////////////////
//////////////////////////////////////////
Block* _blocks[5]; // declaration in class

/////////////////////////////////////////
////////////////////////////////////////
void Driver::NextActiveBlock()
{
    if( _activeBlock == 0 || _activeBlock == _blocks[MAX_BLOCKS-1] )
        _activeBlock = _blocks[0];
    else
        _activeBlock += sizeof( _blocks[1]);  //problem is here.
}
//////////////////////////////////////////
//////////////////////////////////////////


Ok, _blocks is an array of pointers to Block objects.... so Block**
So i should be able to increment the _activeBlock from one element to the next by adding the size of the pointer within the array (should be 4).

But even if i just replace "sizeof(_blocks[1])" with "4".... _activeBlock doesn't end up pointing to the next element in the list.

Please note:  I realize that I could just increment an index into the array but I'm fiddling around with pointer arithmetic.  If i'm misunderstanding the way memory is allocated when a array of pointers is declared... can someone correct me or fill me in?

Thanks for your time!
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