2.直观打印二叉树

首先，Node.java文件同上
然后打印：

public class printTree {

    public String getSpace(int num)
    {
        String space = " ";
        StringBuffer buf = new StringBuffer("");
        for(int i=0;i<num;i++)
        {
            buf.append(space);
        }
        return buf.toString();
    }
    
    public void printBinaryTree(Node head)
    {
        System.out.println("BinaryTree:");
        printInOrder(head,0,"H",17);
        System.out.println();
    }
    
    public void printInOrder(Node head,int height,String to,int len)
    {
        if(head == null)
        {
            return;
        }
        printInOrder(head.left, height+1, "v", len);
        
        String val = to+head.value+to;
        int lenV = val.length();
        int lenL = (len - lenV)/2;
        int lenR = len - lenL - lenV;
        val = getSpace(lenL)+val+getSpace(lenR);
        System.out.println(getSpace(height*len)+val);
        
        printInOrder(head.right,height+1,"^",len);
    }
}