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Explain different types of tree traversals technique with examples. Also write recursive function for each traversal technique
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1. To traverse a binary tree means to visit each node of the tree exactly once in a systematic fashion.

2. Binary tree is non-linear data structure. Hence, we canâ€™t traverse it like a linked list is a sequential manner but it requires a different approach.

3. We mainly have three algorithms for traversing binary tree. A. Pre-order Traversal

B. In-order Traversal

C. Post-order Traversal

4. Consider the Tree

1. Pre-order traversal:-To traverse a non-empty binary tree by pre-order method, the following operations are performed recursively until all nodes are visited: i. Visit the root node. ii. Traverse the left sub-tree fully. iii. Traverse the right sub-tree.

The pre-order traversal of above tree is A,Q,W,Z,C,H,G,D

     void printPreorder(struct Node* node)
{
if (node == NULL)
return;

/* first print data of node */
cout << node->data << " ";

/* then recur on left sutree */
printPreorder(node->left);

/* now recur on right subtree */
printPreorder(node->right);
}

2. In-order Traversal:- To traverse a non-empty binary tree by in-order method, the following operations are performed recursively until all nodes are visited:

i. Traverse the left sub-tree.

ii. Now, visit the root node.

iii. Then, finally traverse the right sub-tree.

The in-order traversal of the tree is Q, Z, W, C, A, H, D, G

void printInorder(struct Node* node)
{
if (node == NULL)
return;

/* first recur on left child */
printInorder(node->left);

/* then print the data of node */
cout << node->data << " ";

/* now recur on right child */
printInorder(node->right);
}

1. Post-Order traversal:- To traverse a non-empty binary tree by post-order method, the following operations are performed recursively until all nodes are visited:

i. Traverse the left sub-tree.

ii. Now, move to the right sub tree

iii. Then, finally visit the root node.

The post-order traversal of the tree is Z, C, W, Q, D, G, H, A

void printPostorder(struct Node* node)
{
if (node == NULL)
return;

// first recur on left subtree
printPostorder(node->left);

// then recur on right subtree
printPostorder(node->right);

// now deal with the node
cout << node->data << " ";
}