1 public class BinaryTreeNode
2 {
3 public Object data;
4
5 public BinaryTreeNode leftPointer;
6
7 public BinaryTreeNode rightPointer;
8
9 public BinaryTreeNode(Object data)
10 {
11 this.data = data;
12 }
13
14 }
15
16 public class Solution
17 {
18 public void preOrder(BinaryTreeNode node)
19 {
20 if(node == null)
21 {
22 return;
23 }
24
25 visit(node);
26
27 if(node.leftPointer != null)
28 {
29 preOrder(node.leftPointer);
30 }
31 if(node.rightPointer != null)
32 {
33 preOrder(node.rightPointer);
34 }
35 }
36
37 public void visit(BinaryTreeNode node)
38 {
39 System.out.println(node.data);
40 }
41
42 }
