Java数据结构之二叉查找树

package JavaProject;

public class TestBinarySearchTree {
	public static void main(String[] args) {  
		BinarySearchTree BiSTree  = new BinarySearchTree();  
		BiSTree.insert(BiSTree.root,2);
		BiSTree.insert(BiSTree.root,4);
		BiSTree.insert(BiSTree.root,12);
		BiSTree.insert(BiSTree.root,45);
		BiSTree.insert(BiSTree.root,21);
		BiSTree.insert(BiSTree.root,6);
		BiSTree.insert(BiSTree.root,111);
		System.out.printf("二叉树的前序遍历为：");
		BiSTree.preOrder(BiSTree.root);  
		System.out.printf("\n二叉树的中序遍历为：");
		BiSTree.inOrder(BiSTree.root);  
		System.out.printf("\n二叉树的后序遍历为：");
		BiSTree.postOrder(BiSTree.root);  
	}  
}  
class BinarySearchTree{
	class Node{
		public int data;
		public Node left;
		public Node right;
		public Node(int data){
			this.data = data;
			this.left = null;
			this.right = null;
		}
	}
	int ans;
	public Node root;
	public BinarySearchTree(){
		root = null;
	}
	public void insert(Node node,int element){
		if(root == null){
			root = new Node(element);
		}
		else{
			if(element < node.data){
				if(node.left == null){
					node.left = new Node(element);
				}
				else{
					insert(node.left,element);
				}
			}
			else{
				if(node.right == null){
					node.right = new Node(element);
				}
				else{
					insert(node.right,element);
				}
			}
		}
	}
	public void preOrder(Node node){  
		if(node != null){  
			System.out.print(node.data + " ");  
			preOrder(node.left);  
			preOrder(node.right);  
		}  
	} 
	public void inOrder(Node node){  
		if(node != null){  
			inOrder(node.left);  
			System.out.print(node.data + " ");  
			inOrder(node.right);  
		}  
	}  
	public void postOrder(Node node){  
		if(node != null){  
			postOrder(node.left);  
			postOrder(node.right);  
			System.out.print(node.data + " ");  
		}  
	}  
}