Traversal of binary tree: A node is visited only once in the traversal of the binary tree. There are three main types of traversal methods in the binary tree.

1. In-order traversal
2. Pre-order traversal
3. Post-order traversal

In-order traversal:

In the in-order traversal method, the left child and left subtree are traversed first, afterward the root tree and then the right children or the right subtree are traversed.

Algorithm of In-order traversal

Example: Find the in-order traversal for this tree.

Solution.

Step 1: Left sub-tree is 1 → 4 → 9

Step 2: Root node is 5

Step 3: Right sub-tree is 5 → 7 → 2 → 6 → 3

In-order Traversal = 1 → 4 → 9 → 5 → 5 → 7 → 2 → 6 → 3

Pre-order Traversal:

In the pre-order traversal method, the root node is traversed first, then the left subtree, and then the right subtree is traversed.

Algorithm of pre-order traversal

Example: Find the pre-order traversal for this tree.

Solution.

Step 1: Root node is 5

Step 2: Left sub-tree is 4 → 1 → 9

Step 3: Right sub-tree is 6 → 7 → 5 → 2 → 3

Pre-order Traversal = 5 → 4 → 1 → 9 → 6 → 7 → 5 → 2 → 3

### Post-order traversal:

In the post-order traversal method, the left child and left subtree are traversed first, then the right subtree is traversed, and then the root node.

Algorithm of Post-order traversal

Example: Find the Post-order traversal for this tree.

Solution.

### Applications of binary tree

1. The binary search tree is used in many search applications.
2. Nowadays, a binary Space Partition is used for every 3D game.3.
3. The binary tree is used in every high bandwidth router that stores the router table.