Q. Write down a non recursive algorithm to traverse a binary tree in order.                   

Ans:

Non - recursive algorithm to traverse a binary tree in inorder is as follows:-

Initially in the beginning   push NULL  onto STACK  and then set  PTR  = ROOT. Then    repeat the steps written below until   NULL is popped from STACK.

i.      Continue down the left -most path rooted at PTR, pushing each node N onto STACK and stopping when a node     N    with no left    child     is   pushed    onto

STACK.

ii.    [Backtracking.] Pop and  process the nodes on

STACK. If the NULL is popped then Exit. If a node N

Having a right child R(N) is processed, set PTR = R(N) (by assigning PTR = RIGHT[PTR] and return to the Step(a)).