
296 Data Structures Using C
7.4.3.2 Preorder Travel (V-L-R) This order of travel, i.e., V-L-R requires that while travelling the
binary tree, the data of the visited node be processed first before the left sub-tree of a node is travelled.
Thereafter, its right sub-tree is travelled.
Consider the binary tree given in Figure 7.18.
Its root node is pointed by a pointer called Tree.
The travel starts from root node A and its
data is processed (V). As it has a left child, we
move to B (L) and its data is processed (V). As
B has no left child, the right child of B needs
to be travelled which is also NULL. Thus, the
travel of B is complete and