#: 8700 S3/Languages
    12-Dec-90  21:42:10
Sb: #8674-#Dynamic Structure Alloc
Fm: Jay Truesdale 72176,3565
To: Jay Truesdale 72176,3565 (X)

Pete:

Thanks for the confirmation about why I need to worry about what the pointer
points to (pointer math) and why I need to cast the pointer returned by malloc.

I think that I have to do the same cast for the same reasons to do what I
really want to do, reference down the tree.  If I want to get the key value
contained in the left node while "at" the root node then

 (root_ptr->lp)

references the pointer field in the root node which contains a pointer to the
next node.  I want to dereference this to get what this points to (the next
node).  The pointer contained in this field is of type b_tree_rec so I need to
cast the de-reference operation to the proper type???

I then can use the -> operator to retrieve the contents to the next node like
this:

         ((struct b_tree_rec *)(root_ptr->lp))->key

This appears to work as my short test program gets the results I expected. I'm
not sure why I need to cast the de-reference operation as I declared the "lp"
field as being a pointer to type b_tree_rec in the structure template
definition right before main.

Thanks in advance,

-J



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