java 二叉树创建

class BinaryTree {
 static class Node {
   char data;
   Node left;
   Node right;
   int i;
  } public static char[] dataArray = new char[] { 'a', 'b', ' ', 'd' };
 public static Node creatRoot(Node node) {
   if (node.i < dataArray.length) {
    if (node.data == ' ')
     node = null;
    if (node != null)
     node.data = dataArray[node.i];
    node.left = creatLeft(node);
    node.right = creatRight(node);  }
   return node;
  } public static Node creatLeft(Node node) {
   if (node != null) {
    node.left = new Node();
    node.left.i = 2 * node.i + 1;
    creatRoot(node.left);
   }
   return node.left; }
 public static Node creatRight(Node node) {
   if (node != null) {
    node.right = new Node();
    node.right.i = 2 * node.i + 2;
    creatRoot(node.right);
   }
   return node.right;
  } public static void main(String args[]) {
   Node node = new Node();  node = creatRoot(node);
  System.out.print(node.data + " " + node.left.data + " "
     + node.right.data + " " + node.left.left.data); }
}