// Definiton of TreeNode in Java
/*
public class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;
 
    public TreeNode(int val) {
        this.val = val; 
        left = null;
        right = null; 
    }
}
*/
 
public class DFS {
    
    public void inorder(TreeNode root) {
        if (root == null) {
            return;
        }
        inorder(root.left);
        System.out.println(root.val);
        inorder(root.right);
    }
 
    public void preorder(TreeNode root) {
        if (root == null) {
            return;
        }
        System.out.println(root.val);
        preorder(root.left);
        preorder(root.right);
    }
 
    public void postorder(TreeNode root) {
        if (root == null) {
            return;
        }  
        postorder(root.left);
        postorder(root.right);
        System.out.println(root.val);
    }
    
}```