In-order traversal

Steps

• Traverse the left sub-tree in in-order
• Visit the root
• Traverse the right sub-tree in in-order

Algorithm

• Step 1: Repeat Steps 2 to 4 while TREE != NULL
• Step 2: INORDER(TREE -> LEFT)
• Step 3: Write TREE -> DATA
• Step 4: INORDER(TREE -> RIGHT)
  [END OF LOOP]
• Step 5: END

C Function

Example

Traverse the following binary tree by using in-order traversal.

• print the left most node of the left sub-tree i.e. 23.
• print the root of the left sub-tree i.e. 211.
• print the right child i.e. 89.
• print the root node of the tree i.e. 18.
• Then, move to the right sub-tree of the binary tree and print the left most node i.e. 10.
• print the root of the right sub-tree i.e. 20.
• print the right child i.e. 32.
• hence, the printing sequence will be 23, 211, 89, 18, 10, 20, 32.