Tree traversals-Very Important Basics in Trees

Question: Inorder Traversal

Algorithm: 
Left-Root-Right

CODE:
class Node {
    int data;
    Node left, right;
   Node(int item)    {
        data = item;
        left = right = null;
    }
} 
class Solution
{
   /* Prints preorder traversal of Binary Tree.  In output
      all keys should be separated by space. For example
      preorder traversal of below tree should be "10 20 30"
         10
       /      \ 
    20       30 */
    void inOrder(Node root)
    {
       // Your code goes here
       if(root==null){return;}
       inOrder(root.left);
       System.out.print(root.data+" ");
       inOrder(root.right);
    }

}

Question: PreOrder traversal

Algorithm: Root-Left-Right

CODE:
class Node {
    int data;
    Node left, right;
   Node(int item)    {
        data = item;
        left = right = null;
    }
} 
class Solution
{
   /* Prints preorder traversal of Binary Tree.  In output
      all keys should be separated by space. For example
      preorder traversal of below tree should be "10 20 30"
         10
       /      \ 
    20       30 */
    void preorder(Node root)
    {
       // Your code goes here
       if(root==null){return;}
       System.out.print(root.data+" ");
       preorder(root.left);
       preorder(root.right);
    }

}

Question: PostOrder Traversal

Algorithm: Left-Right-Root

CODE:
class Node {
    int data;
    Node left, right;
   Node(int item)    {
        data = item;
        left = right = null;
    }
} 
class Solution
{
    void postOrder(Node root)
    {
       if(root==null){return;}
       postOrder(root.left);
       postOrder(root.right);
       System.out.print(root.data+" ");
    }

}
Question: Level Order Traversal

Algorithm: 
1.Create an empty queue
2.tempNode=root
3.Loop while tempNode is not null
3.1.Print tempNode.data
3.2.Enqueue all children of tempNode
3.3.Dequeue a node and assign it to tempNode

CODE:
class Solution
{
    void levelOrder(Node node) 
    {
        // Your code here
        Queue <Node> queue= new LinkedList<Node>();
        queue.add(node);
        while(!queue.isEmpty()){
            Node tempNode= queue.poll();
            System.out.print(tempNode.data+" ");
            if(tempNode.left!=null){
                queue.add(tempNode.left);
            }
            if(tempNode.right!=null){
                queue.add(tempNode.right);
            }
        }
    }

}