How To Traverse Binary Trees

There are three standard ways of traversing a binary tree T with root R. These three algorithms, called preorder, inorder and postorder, are as follows:

Preorder (Root Left Right)

• Process the root R.
• Traverse the left subtree of R in preorder.
• Traverse the right subtree of R in preorder.

Inorder (Left Root Right)

• Traverse the left subtree of R in inorder.
• Process the root R.
• Traverse the right subtree of R in inorder.

Postorder (Left Right Root)

• Traverse the left subtree of R in postorder.
• Traverse the right subtree of R in postorder.
• Process the root R.