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I can traverse the binary search tree using recursion easily, but I don't have an idea about traverse without recursion so please anyone explain,.....

Meena Patel
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    have you tried anything yourself at first. please post the codes where you are stuck. – Mohammad Tauqir Oct 08 '15 at 17:40
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    You should probably read Wikipedia page on [Tree Traversal](https://en.wikipedia.org/wiki/Tree_traversal) there are multiple algorithms there on how to do it with and without recursion. – Edwin Dalorzo Nov 22 '21 at 17:07

1 Answers1

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yes, you can do it with stack. you have to take stack here the algorithm for p reorder, in-order and post-order traversal in iterative way (non recursive way/method) of binary search tree. Hope you will get properly.

p re order:

1) Create an empty stack node_Stack and push root node to stack.

2) Do following while node_Stack is not empty.

-> Pop an item from stack and print it.

-> Push right child of popped item to stack

-> Push left child of popped item to stack

in-order:

1) Create an empty stack S.

2) Initialize current node as root

3) Push the current node to S and set current = current->left until current is NULL

4) If current is NULL and stack is not empty then 

 -> Pop the top item from stack.

 -> Print the popped item, set current = popped_item->right 

 -> Go to step 3.

5) If current is NULL and stack is empty then we are done.

post-order:

1.1 Create an empty stack

2.1 Do following while root is not NULL

-> Push root's right child and then root to stack.

-> Set root as root's left child.

2.2 Pop an item from stack and set it as root.

-> If the popped item has a right child and the right child 
   is at top of stack, then remove the right child from stack,
   push the root back and set root as root's right child.

-> Else print root's data and set root as NULL.

2.3 Repeat steps 2.1 and 2.2 while stack is not empty.

Ankur Lathiya
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