# Binary Tree InOrder traversal in java

If you want to practice data structure and algorithm programs, you can go through data structure and algorithm interview questions.

This is 4th part of java binary tree tutorial.

In this post, we will see about InOrder binary tree traversal in java.

#### InOrder traversal:

In InOrder traversal,each node is processed between subtrees.In simpler words,Visit left subtree, node and then right subtree.
Steps for InOrder traversal are:
• Traverse the left subtree in InOrder.
• Visit the node.
• Traverse the right subtree in InOrder.

There can be two ways of implementing it

• Recursive
• Iterative

Recursive solution:
Recursive solution is very straight forward.Below diagram will make you understand recursion better.

Code for recursion will be:

Iterative solution:
For recursion, we use implicit stack. So here to convert recursive solution to iterative, we will use explicit stack.
Steps for iterative solution:

1. Create an empty stack s and Initialize current node as root
2. Push the current node to s and set currentNode = currentNode.left until currentNode is NULL
3. If currentNode is NULL and s is not empty then
• Pop the top node from stack and print it
•  set currentNode = currentNode.right
• go to step 2
4. If stack is empty and currentNode is also null then we are done with it

Lets create java program for InOrder traversal:

Run above program and you will get following output:

## Java Binary tree tutorial:

Please go through java interview programs for more such programs.